Intermittent fasting for health and longevity

One of the primary topics covered on this blog is intermittent fasting (IF).  Many approach IF as a diet or weight loss method.  I know from research, personal experience and conversations with others that IF can indeed be an effective way to drop unwanted pounds.  However, viewing IF as merely a new way to diet entirely misses what I believe is the most important reason to pursue it:  the activation of hormetic processes that foster improved health, keep degenerative diseases at bay, and hold out the promise of a longer, more vibrant life.  These benefits are a known consequence of calorie restriction, but intermittent fasting offers a more comfortable and versatile way to reap the benefits of calorie restriction without the sense of deprivation, the loss of lean body mass, and the metabolic risks that have been associated with simple calorie restriction.

It is because I’ve found intermittent fasting to be an attractive practice, both scientifically and personally, that I was so excited to be invited to give a lecture on IF at The 3rd Door, an innovative health and fitness studio, cafe and social center in downtown Palo Alto. The fitness director at The Third Door, Johnny Nguyen, is himself an advocate and practitoner of IF, which he blogs about with great flair and common sense at The Lean Saloon. The talk gave me an opportunity to reframe intermittent fasting in the terms of the philosophy of Hormetism, or applied hormesis that I write about on this blog.  I believe that the framework of hormesis helps to make sense of why IF works, and why it is so much more than a diet.

What follows is a video of my talk on the benefits of intermittent fasting, presented on May 18, 2011 at The 3rd Door.  I would like to thank Dianne Giancarlo and Johnny Nguyen for inviting me to speak, Vaciliki Papademetriou for technical assistance, Francesca Freedman for introducing me to The Third Door, Tom Merson for the still photos and Ken Becker for the masterful video production.

The talk is divided in to five sections for ease of viewing.  It was followed by a 30 minute question and answer session, which I will upload as soon as the video production is complete:

Part 1:  The benefits of calorie restriction

 

Part 2:  Calorie restriction and hormesis

 

Part 3:  Intermittent fasting and diet myths

 

Part 4:  How intermittent fasting turns you into a “flex fuel vehicle”

 

Part 5:  Practical advice on how to get started with intermittent fasting

Within the coming week, I will add here a recording of the 30-minute question and answer session following the talk.

If the above talk was of interest, you can find more detailed information in two of my other posts:

Happy fasting!

 

 

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92 Comments

  1. Katie J.

    Thanks for posting this. I enjoyed your talk. My short experience with IF has been very positive. I’ve gotten into it slowly, but only as an accident as I didn’t know about IF initially. 4 months of low carb, skipping a meal and then finding it was just as easy to skip 2 meals a day. Love having fewer dishes to clean up:-)

    Wanted to refer you to an interesting book written in 1900 by Edward Dewey. Dewey was a civil war doctor who through observation found that fasting was really the best way to treat sick people. He describes the barbaric practice of forcing milk and whiskey down the throats of the ill in an effort to feed them. His book is titled, The No Breakfast and Fasting Cure and it is available as a free download from Project Gutenberg.

    Reply
  2. Intermittent Fasting is possibly one of the coolest biohacking techniques out there. If you can really call something we’ve been doing for millions of years a “hack”.

    I’ve been doing it for years with huge improvements in my ability to use fatty acids during exercise instead of carbs, and I can go faster, longer, and harder than before.

    There have been some excellent studies on improved athletic performance using IF, including an increase in VO2 Max by up to 75%, an increase in citrate sythase, and in carbohydrate storage.

    Most of the studies showing that it is detrimental to performance were not from actual physical markers, but from general fatigue of the subjects. There really is no other explanation since in rats and other animals there has been no decrease in performance, and rats never say to themselves “I’m getting tired”, they just keep going. Glucose levels were the same whether or not it was in a fasted state- so no actual loss in available fuel.

    Almost all the current arguments against IF are not based on any good data, and it’s really impossible to argue with implementing it to some degree.

    I thought you gave an excellent overview and can’t wait to see more on the subject:)

    -Armi

    Citations:

    http://www.ncbi.nlm.nih.gov/pubmed/20452283

    http://www.ncbi.nlm.nih.gov/pubmed/3536834

    Reply
    • Todd

      Armi,

      Thanks for the citations to those two articles. I had not seen them before, but they confirm results I had seen in other research.

      My own experience with fasted workouts is that my training performance suffers somewhat, at least initially, but this leads to beneficial adaptations. As a case in point, my running speed suffered during fasted training for 24-hour relay race I took part in, but I ate well, including carbs, during the race itself and my performance was significantly improved vs. the same race a year ago.

      Todd

      Reply
  3. Arthur

    Thanks, very interesting talk.

    I would have liked to hear a bit more about your personal experiences with intermittent fasting: how did you get started, how are you doing it now, what changes did you notice?

    Reply
    • Todd

      Arthur,

      Glad you liked the talk. I got started with IF about a year ago when I realized that low carb and fasting operate by the same principle — insulin lowering. I read about IF on a few websites, including Fast-5, Eat-Stop-Eat and Leangains and began to experiment with it. At that time I had also found some benefit in following the Shangri-La Diet of Seth Roberts, which I believe works by lowering preprandial insulin (See my post on Flavor control diets), so I began to experiment with IF and document my experience and explanation on Roberts’ blog forum in an extended thread on appetite suppression, which I’ve linked HERE. You might find it interesting reading.

      My current practice is generally eating 1 or 2 meals each day (usually lunch and/or dinner), but occasionally eating all 3 meals or fasting for 1, 2 or 3 days. So I really do mix it up, along the lines that Art DeVany recommends in his book The New Evolution Diet, which I highly recommend. I eat a mostly Paleo / low carb diet, but I make plenty of exceptions. I rarely eat rice, pasta or potatoes, but I will have bread, pastries, fruit and ice cream a few times a week, and I enjoy alcohol in moderation 2 or 3 days a week.

      The biggest change I find since starting IF (besides losing a lot of weight) is that it gives me a lot of energy and a feeling of freedom. I’m not often hungry, but I do experience hunger at times. I realized that a certain degree of hunger is not a bad thing, and it makes you feel energetic and alive. I prefer that feeling vastly to being overstuffed, bloated and lethargic.

      Todd

      Reply
      • “I realized that a certain degree of hunger is not a bad thing, and it makes you feel energetic and alive. I prefer that feeling vastly to being overstuffed, bloated and lethargic.”

        Yes, exactly! I often feel more energized, physically and mentally, when in a fasted state vs. a fed state.

        By the way, I am currently nursing my 18 month old, and do fast. I waited until he was a year old, eating solids, and my milk production was well-established before slowly trying IF. I am also careful to make sure I’m hitting the ON of CRON, eating a nutrient dense, Paleo/Primal diet (thus making sure I get enough nutrients for both me and my son – though most of his nutritional needs are now being me from eating, not nursing). Anyway, it is possible to IF when nursing, but only when following certain parameters and proceeding with great caution.

        I love your blog, Todd. Keep up the great work!

        Reply
      • Tim

        That energetic and alive feeling during hunger is probably caused by cortisol or adrenalin, right? You didn’t even mention cortisol in the talk which I otherwise really enjoyed. How is cortisol affected during intermittent fasting? There’s no risk that there might be too much of those stress hormones? Have you monitored cortisol on yourself to see what happens during IF?

        Reply
        • Todd

          Tim, you raise an interesting and somewhat controversial question. It is true that cortisol will temporarily rise even during short term fasting. This has alarmed some people, like Chris Kressler. But as with any insulin or any other hormone, cortisol is neither “good” nor “bad” in itself. The problem is imbalance or chronic elevation. Just as is the case with insulin (but in the opposite direction), chronically elevated cortisol levels lead to health problems such as muscle catabolism, adrenal fatigue, and an increase in abdominal fat. But this does not appear to be an issue for short or “acute” increases in cortisol. In fact, just the opposite: acute cortisol has many important health benefits, including regulation of glucose metabolism and modulation of blood pressure and immune function. In periodic bursts or cyclic release, it improves short term memory and enhances deep sleep. I think that one could almost say that our hormones were designed or “selected” to work on a cyclic basis. It’s hard to think of any that don’t work that way.

          The other factor to consider is the background of mental, emotional and physical stress. Chronic stress of any kind will tend to elevate cortisol levels–and do so chronically. If you practice IF and the rest of your life is stressful, you might be making the problem worse. That includes excessive cardio and weight lifting, not just hectic living. But if you make it a point to balance and these stresses and alternate them with periods of rest and recovery, then your “basal” cortisol level should be OK. (One of the best books about this is Jim Loehr’s “The Power of Full Engagement”, which I discussed in my post on Stress management and toughness training). If you do have a concern, testing for cortisol involves a relatively simple saliva test. If you take this test, I would suggest returning to a normal 3-day meal pattern during the 2 days before the test, to be sure you are measuring a baseline level, not an acute spike.

          Todd

          Reply
        • Tim

          I can’t reply to your answer (weird) so I guess I’ll answer to myself.

          How is blood sugar maintained during a day without food? I hear it’s cortisol that will raise the blood sugar if it gets too low during IF. What about glukagon, isn’t its purpuse to raise low blood sugar? A day without food, how often will cortisol have to be elavated in order to maintain the blood sugar? I guess some IF website has this information so I’ll eventually find it, but you can answer if you want to :)

          Reply
          • Todd

            Tim,

            You don’t need cortisol to supply glucose during fasting. The two normal ways that the body supplies glucose are glycogenolysis and gluconeogenesis. During fasting, if blood sugar starts to drop, glucagon kicks in to activate glycogenolysis, or breakdown of stored glycogen to glucose. Once glycogen supplies are low (after about a day or so), gluconeogensis will kick in to convert lactate and amino acids from the protein in you muscles. However, your body will also adapt by running on less glucose and more fat and ketones. This will spare you the need to supply as much glucose.

            Reply
        • Tim

          Interesting. Do you mean that cortisol is needed for gluconeogenesis, but not glycogenolysis? After googling this a bit it’s not at all clear to me how this works. I guess saliva testing is what gives the best answers to what happens in my own body. I’ll have to address my adrenal fatigue before I try this stuff though.

          Reply
          • Todd

            Tim, I never said that cortisol is required for either gluconeogenesis or glycogenolysis.

            Reply
      • I came across your blog today after listening to a podcast by Dr. John Briffa. I’m going to try to integrate these hormetic ideas into my lifestyle. I’d previously read some of Art DeVany’s posts and PDF downloads, and his thinking on stochastism of biological systems (and many others, including economics, which is an offshoot of biology) has heavily influenced my thinking since then.

        What follows is all theoretical — it reflects my current thinking — but I do plan on starting it immediately and testing it with some vigour. I intend to do the following re: diet:

        Flip three coins (or one coin three times) each day. The generated randomness will then cause me to embrace one of the following for today:

        Triple Heads: Modified Fast [1:8 chance]
        Mixed: Paleoesque High-Fat, Moderate Protein, Low-Carb [6:8 chance]
        Triple Tails: Whatever [1:8 chance]

        Details are below, with much of this gleaned from Dr. Andreas Eenfeldt’s LCHF recommendations, as well as other sources and my own musings:

        ### Triple Heads: Modified Fast

        - Coffee: Hot or cold, with or without cinnamon or cream or coconut oil.

        - Tea: Post-fermented, black, oolong, green, yellow, or white. Hot or cold, with or without cinnamon or lemon or natural lemon flavour — which, unlike lemon, has no remaining Vitamin C.

        - Tisane: Aka herbal tea. Hot or cold, with or without cinnamon or lemon or natural lemon flavour — which, unlike lemon, has no remaining Vitamin C.

        - Water

        ### Mixed: Paleoesque High-Fat, Moderate Protein, Low-Carb — Above Plus

        - Eggs: Preferably grass-fed. Wonderful, wonderful source of food.

        - Meat: Any type, including beef, pork, or game meat, etc. Feel free to eat the fat on the meat. If possible try to choose organic or grass fed meat.

        - Poultry: Any type, including chicken, turkey, or duck, etc. Feel free to eat the skin on the poultry. If possible try to choose organic or grass fed poultry.

        - Fish: All kinds: Fatty fish such as salmon, mackerel, or herring are great. Avoid breading.

        - Shellfish: All kinds. Avoid breading.

        - Natural Fat: Using butter and cream when you cook can make your food taste better and make you feel more satiated. Try a Béarnaise or Hollandaise sauce; check the ingredients or make it yourself. Clarified butter (including ghee), fish oil, other marine lipids, tallow, lard, coconut oil, palm oil, olive oil, avocado oil, macadamia nut oil, and walnut oil are also good options. Canola oil and peanut oil can be used in a pinch, although they’re not as good. Cold-pressed sesame seed oil on occasion for flavoring is fine. MCT (medium chain triglycerides) oil — a particularly healthful extract usually of coconut oil — although butter is quite high in MCT as well — is excellent.

        - High-Fat Dairy Products: Select high-fat options like real butter, cream, sour cream, Greek/Turkish yogurt, and cheese. Avoid flavoured, sugary, and low-fat products.

        - Low-Starch Seeds: Choose low-starch options like sesame seeds, pumpkin seeds, and squash seeds. Be careful with flax seeds because they are high in the less than ideal fraction of Omega-3: Alpha-linolenic acid — a precursor to both eicosapentaenoic acid and docosahexaenoic acid, but not conferring the same cardiovascular benefits — statistically linked in excess to increased prostrate-cancer rates.

        - Low-Starch Nuts: Macadamia nuts, Brazil nuts, and walnuts are the best nuts, with almonds and hazelnuts/filberts being good too. Pistachios are OK.

        - Low-Starch Legumes: Snowpeas, non-dried peas, and green beans are acceptable.

        - Low-Starch Vegetables: Leafy greens, such as lettuce, spinach, Asparagus, and green onions; cabbage, such as cauliflower, broccoli, cabbage, and Brussels sprouts; eggplant; mushrooms; garlic, onions; carrots; beats; ginger; etc.

        - Low-Sugar Fruit: Avocado, olives, coconut, zucchini, cucumber, lemons, limes, tomato, peppers, etc. Fresh, frozen, or canned.

        - Berries: Blueberries, strawberries, raspberries, blackberries, cranberries, etc. Fresh or frozen.

        - Dark Chocolate: 70% cocoa or above.

        - Dry Wine: Regular red or dry white.

        - Liquor: Whisky, rum, gin, tequila, brandy, vodka, etc.

        - Spices: Black pepper, cinnamon, tumeric, chilli peppers, garlic, ginger, rosemary, basil, bay leaves, cumin, dill, fennel, garlic, hyssop, oregano, saffron, sage, and thyme, etc.

        - Salt: Iodised table salt, sea salt, chicken broth, beef bouillon, etc.

        ### Triple Tails: Whatever — Above Plus

        - Unnatural Fat: Margarine, soybean oil, safflower oil, sunflower seed oil, cottonseed oil, corn oil, wheat germ oil, rice brain oil, mustard seed oil, grape seed oil, flax seed oil. Have few if any health benefits. Various problems including many of them are industrially-imitated fats with unnaturally-high content of Omega-6 — statistically linked in excess to asthma, allergies, and other inflammatory diseases; others are the wrong fraction of Omega-3: Alpha-linolenic acid — a precursor to both eicosapentaenoic acid and docosahexaenoic acid, but not conferring the same cardiovascular benefits — statistically linked in excess to increased prostrate-cancer rates.

        - Milk

        - High-Starch Seeds: E.g., sunflower seeds.

        - High-Starch Nuts: Chestnuts and cashews.

        - High-Starch Legumes: A rare high-fat legume that is still quite high in starch. Peanut butter has less alfatoxin, a significant problem with peanuts, than peanuts themselves. In one study, roasting at 160 degrees C reduced aflatoxin by 51%. Blanching, or skin removal, reduced it by 27%. Finally, grinding the peanuts into butter removed another 11% of the aflatoxin — probably because of the heat, not the grinding. Also beans, lentils, chickpeas, dried peas, etc.

        - High-Starch Vegetables: Potatoes, sweet potatoes, yams, turnips, squash, pumpkin, etc.

        - Grains: Guten-Free: Rice, wild rice, oats, corn, millet, quinnoa, sorghum, montina, teff, aramanth, buckwheat. | Gluten-Containing: Wheat, barley, rye, triticale.

        - Coconut Milk

        - Non-Berry High-Sugar Fruit: Bananas, mangoes, papayas, pineapples, figs, passion fruits, guavas, kumquats, lychees, persimmons, pomegranates, kiwis, grapes, cherries, plums, nectarines, peaches, apricots, tangerines, melons, oranges, pears, apples, grapefruit, etc.

        - Honey

        - Unnatural Sugar/Fructose: Soft drinks, candy, juice, sports drinks, milk chocolate, doughnuts, cakes, cupcakes, pastries, muffins, ice cream, breakfast cereals.

        - Artificial Sweeteners

        - Beer: Liquid bread. Full of rapidly absorbed carbs.

        I think hormetic principles naturally will fall out of both the coinflips and healthful vs. “unhealthful” food selections, high vs. low carb days, “antinutrient” containing vs. not so much, etc., and even some days where pretty much metabolic poisons are allowed (but hardly mandatory) such as artificial sweeteners — yuck.

        I have started using coin flips for some other, “What should I focus on now for a brief period of time?” decisions involving longer-term projects since it’s one less decision to make a day, and psychologists say that making decisions reduce our capacity to make other decisions. Of course, hormesis probably affects that too, and likely that can be strengthened.

        I particularly like the idea of the coinflips for embracing today’s Paleolithic-influenced stochastically-varied hormetic diet because it should prevent any tendency to eat more in advance of a “Modified Fast” day or less in advance of a “Whatever” day.

        That said, I could see tossing that randomness aside, perhaps temporarily, if I have a reason to choose otherwise for a given day: maybe a wedding, hopefully not mine.

        :-P

        Reply
        • Todd

          Chris,

          That’s quite a list! Many good ideas in there, particularly in your middle, “paloesque” category. My first thought would be to significantly increase the frequency of intermittent fasting. Triple heads comes only once every 8 days on average. About 3-4 days a week, I typically eat only once a day, and rarely do I eat 3 meals a day.

          Coin flipping does have the virtue of forced randomness, so it might be interesting to try. I prefer to let my intuition, and to some extent circumstances, guide me. If I’m on a long flight or traveling, I have no problem skipping airplane meals because they are so awful. But I will partake of exceptionally good food opportunistically.

          I like your idea of deliberately going “anti-Paleo” every so many days (or meals). I think it maintains physiological flexibility and is psychologically healthful too. I have a post, “Get stronger using stress oscillation” which you might find interesting on the point of allostasis as a means of building resilience.

          Thanks for posting.

          Todd

          Reply
        • Thanks for the link to your post, Todd.

          Few things have been more on my mind for the past couple years than “resilience”, and that is a long story.

          Quick off-topic question:

          You have three checkboxes below this comment, two of which are:

          Notify me of followup comments via e-mail. You can also subscribe without commenting.

          Notify me of follow-up comments by email.

          I didn’t know what was up with that (it was a bit confusing), so I checked both — and received two emails from your system advising me of your comment: one of those was in formatted HTML, the other not.

          It seems a bit redundant, but maybe that’s just me. If you want both checkboxes there for some reason, why not have one be, “Notify me of followup comments via formatted HTML email, and the other, “Notify me of follow-up comments by plain text email.”? [or get rid of one]

          Just a thought. A minor admin point I know!

          Reply
          • Todd

            Chris,

            Thanks for pointing out the issue with the comment follow-up checkboxes. Unfortunately, this is a standard form that came with my WordPress blog software, I didn’t create it, and I can’t go back into edit your settings. If you are getting duplicate notifications, can you edit the settings yourself? If not, I would suggest canceling your subscription and then re-applying, checking just the box you want this time.

            Hope that works. I’d like to keep you as a subscriber. :-)

            Todd

            Reply
  4. Gerry

    Great presentation! My husband and I discovered Fast-5 over a year ago and it is now our lifestyle. We are 57 and 61 years old and were slender most of our lives until the pounds started creeping on about age 50. Husband has lost about 35 pounds effortlessly it seems and can wear his old jeans again. I lost a bit but find IF keeps me from gaining so it is a great maintenance method for me. Your posting of the article on Lee Shurie really helped me look at IF seriously then I found the Fast-5 website to read about that technique. I am going to read your post on the Deconditioning Diet for more reinforcement and new ideas. We have found using IF to be very liberating. I never would have guessed that I could go without eating often. Amazing!!

    Reply
  5. Tim

    Regarding autophagy. I’ve heard a couple of times (I think for instance by Mat Lalonde and Tim Ferris) that one can get the benefits of autophagy with protein fasting and without any other diet constraints. Do you consider this to be true? Could it be the protein fasting that is the key in IF?

    The ability to quickly change from fat burning to carb burning and vice versa sounded appealing. I guess protein fasting is not enough for that.

    Reply
    • Todd

      I’ve heard of the supposed connection between protein fasting and autophagy, but it doesn’t make metabolic sense. This theory is the basis of Mignery’s Protein Cycling Diet. Mignery makes the claim that protein fasting leads to autophagy, but I could not find any evidence for this claim. Instead, his argument takes the following form:

      A. Autophagy is the mechanism of lifespan extension in roundworms, fruit flies, and presumably all animals.
      B. A diet of alternate day protein fasting in fruit flies extends lifespan as much as alternate day total fasting.
      C. Therefore protein fasting promotes autophagy.

      The logic does not work. Protein fasting could extend lifespan for reasons that have nothing to do with autophagy. But my bigger problem is what to eat when you are protein fasting. Mignery suggests a diet high in both fat and carbohydrate during the protein fast. But this will tend to raise insulin levels, and elevated insulin is known to totally suppress autophagy.

      Hope that answers your questions

      Reply
      • Tim

        That study showed suppression of autophagy in the presence of insulin resistance. But you can eat carbs while being quite insulin sensitive and the fasting insulin would drop to normal rather quickly and perhaps not interfere with autophagy (what do I know).

        I’ll probably ask others on their blogs about this and see if they can come up with any references on protein fasting or cycling.

        Reply
        • Todd

          I agree that if you are insulin sensitive you can tolerate carbs and insulin levels will drop between meals. But you still need to allow enough time between meals without eating for autophagy to kick in. Even small snacks can raise insulin enough to shut it down.

          Reply
  6. I was wondering if you have any data comparing IF applied to a plant-based diet with relatively low protein. I have used IF with a Paleo diet and had good success, but I have always wanted to switch back to a more vegan type diet, using protein sources such as hemp seed, pea, artichoke, rice and bean. I would probably include some eggs with that. I have enjoyed the way a Paleo diet has allowed me to effortlessly maintain my weight and muscle mass, but I am bothered by the ethical implications of a diet that supports agri-business and has such a larger carbon footprint. I have come to the conclusion that I would be willing to sacrifice six pack abs to make a contribution to planetary well-being, I would rather not if I didn’t have to do so. I would much rather placate my narcissism while being environmentally responsible if at all possible.

    Reply
    • Todd

      Michael,

      I don’t have data that addresses the comparison you are seeking. “A plant-based diet with relatively low protein” will probably be high in carbohydrates, assuming you are not eat lots of avocados and nuts. But there is no reason you can’t apply IF to such a diet; as long as you allow at least 12 uninterrupted hours per day without eating, you should lower your insulin for long enough to reap the benefits of autophagy, mitohormesis, and other processes that kick in with IF.

      We can probably get by with less meat and fish, but I would never want to give them up, because I think they are essential to both physcial and mental health. Regarding sustainability, I think that industrial agriculture is not necessarily that superior to industrial meat raising. If we vote with our wallets and support more sustainable, more healthful “paleo” meat and plant sources, the market will begin to adjust to demand.

      One often overlooked factor is how the amount of food we eat impacts the economy: If more people practice IF/CR, we’ll begin to be satisfied with significantly less food, but food which is more nutritious and deliciously satisfying. In addition, the amount of food waste is also a major source of inefficiency in the food supply. One of the drivers of this waste is the abundance of very inexpensive but nutritionally worthless “food” that crowds supermarket aisles: all kinds of chips, sodas and puffy fillers. I probably eat about half as many grams of food per day (including beverages) as I used to before shifting to real food and practicing IF. Imagine the cost savings and the reduction in the shear mass and volume of “food” — including huge savings in shipping, warehousing, etc. — that could result if a large percentage of us learned how to reduce the volume of food that we “need”.

      If you include a judicious amount of nutritious meat and fish in your diet, and curb your appetite using IF, you might just end up eating in a manner that is more sustainable than if you were a voracious vegan!

      Reply
      • Hi Todd,

        Thanks for getting back to me with some valuable feedback. You are right about industrial agriculture, it is pretty hard to avoid corporate enterprise, whether plant or animal based. My reasons for wanting to go more plant based, however, were more related to animal cruelty than anything else. I have explored more humane options for obtaining meat and fish, but it is hard to deny that a pig, or even a chicken or fish for that matter, is a conscious enough being that I experience reservations about causing their suffering. I don’t want to sound like a wuss, but I would never eat my dog and by all indications a pig is at least as conscious and intelligent. If I raised animals, even fish, and got to know them as individuals, I would never be able to kill them and eat them, anymore than I could my dog. They have too obvious of a sense of self and clear desire for self-preservation. I know that killing can’t be avoided in this universe but it seems like a matter of moral responsibility to eat as low on the food chain as possible without sacrificing good health.

        As I said, I have been eating Paleo for about a decade now, but these issues never stopped bothering me. Recently I read the book “Eating Animals” that brought the issue to the front for me. I also saw the movie “Forks Over Knives” that seemed to present pretty solid empirical proof that a grain based diet could be healthy. Though I was privy to the debate between Dr. Cordain and Dean Ornish, I always felt that Cordain presented a better case until I saw that movie. I also reviewed the Okanawa Study which presents a case for including at least a pretty large amount of grain into the diet and pretty much using animal food for a condiment.

        I don’t want to be dogmatic one way or the other and it seems like there is a fair amount of data supporting both dietary choices. It is such an absurdly heated debate in the blogoshere. If neither choice is a definitive winner, however, I would tend to go with what seems to me to be a more moral choice.

        In any case, I really appreciate your info on IF. I am so glad that an eating style that always seemed intuitively correct to me has been vindicated by sound data. I was getting really tired of the whole grazing thing! I plan to make IF an integral part of my routine for the rest of my life, regardless of how my dietary content evolves.

        I would like to hear your thoughts on the Paleo vs vegan debate, as to why you feel that Paleo is superior, given the data available from both sides.

        Thanks again.
        Michael

        Reply
      • One more thought- another option that I thought might be an answer to my “Omnivore’s Dilemma”, to quote Michael Pollan, would be to control the glycemic load by minimizing grain consumption, increasing fat consumption by maximizing the intake of MUFAs such as coconut oil and olive oil, eat a lot of avocados, nuts and seeds and balancing the inflammatory consumption of omega 6 PUFAs with high ALA containing oils like hemp, flax, chia and canola, and in addition increasing plant protein to a higher ratio by eating eggs from pastured hens, legumes, hemp, and blue-green algae. The only glitch might be that the conversion of ALA to omega 3 might not be adequate to maintain a proper anti-inflammatory 6/3 ratio, but I am not sure about that. It doesn’t seem to me that, if this could be accomplished, there would be any other reason to eat animals, do you?

        Reply
        • Todd

          Michael, I completely respect your principled decision not to eat animals for ethical or even personal reasons. I think that represents a more solid justification for your dietary choice than the supposed health or sustainability arguments.

          Certainly, it is possible to eat a healthful vegetarian diet! It sounds like you are avoiding excessive grains, starches and sugars, focusing on the “good greens” and getting enough good fats. You are right that ALA, the 18-carbon omega-3 fatty acid found in flax oil, does not confer the same neuroprotective, cardioprotective, and anti-cancer benefits as do the longer chain DHA and EPA essential omega-3 fatty acids found in cold water fish. Depending how far down the food chain your ethical considerations extend (would you swat a mosquito or squash an ant?), you might consider supplementation with krill oil, a phospholipid modified version of DHA and EPA that some claim is more effective, mercury free, and more sustainable. Or you can get “vegan” DHA extracted from algae…algal EPA may soon be available as well. You may also want to supplement with B vitamins or a complex equivalent such as yeast extract.

          Reply
  7. Low Carb High Fat + Intermittent Fasting = A Total Success!

    Reply
  8. Michael – please consider reading The Vegetarian Myth before switching to a plant-based diet for ethical reasons. A vegan diet can cause the same problems with fossil fuel waste as a Paleo diet.

    Instead of going vegan, consider buying local, pasture-raised animals to eat, and eating food from your local farmer’s market. By doing so, you will not be supporting industrial, agri-biz. Most local farmers raise and butcher their animals using humane practices. You can even go and visit the farms to see how they operate.

    Just food for thought.

    Reply
  9. JohnD60

    I enjoyed your videos. Your views are highly consistent with my own. I have been doing my own version of IF for about 3 years. Roughly, 6 fasting days a month, 3 of which are 20-24 hour fasts with an hour of cardio near the end, and 3 of which are just 14-18 hours nothing speacial at the end. I believe the punctuated fasts enhance autophagy dramatically. I also have been practicing time restricted carbohydrate consumption for about a year now, typically 6 days a week I will limit my carb intake to a time frame of about 2PM to 9PM. I believe this improves insulin signaling. My diet would be best described as Paleo, though I don’t practice what they preach. I haven’t had any health problems so far, time will tell. I do what I do because it makes sense to me, not because of some questionable lab experiement on rats or worms.

    Reply
  10. Scott Petrich

    I have been following “IF” for about 7 month now and cant say enough good about it. I really just give up only two meals ever other day. During a given week I miss breakfast and lunch about 3 days during the week and a total of 6 meals missed each week.

    I started at 248lbs + within that 7 months time about 10 pounds a month weight loss give or take. I just checked my weight and I now sit at 185lbs, with 6 pack. I would say the worse part of this for me is that I have to always be working abs because of my loose skin. Also really interesting is that I don’t even workout or run as much as I did before and still get the amazing results. I never feel hungry or starved! I would like to say losing the weight is the best part however I cant even understand why I also feel great with increased energy. Additionally I have always been bothered by mild depression and lack of focus and mood issues all seem to be great know.

    Thanks to teachers like Todd and other for making such a fantastic blog.

    Food Intake:All the above, cabs and fats just less of them. I use fish and chicken in place of red meat. I try to stay away from anything pre-pkg from the store and no fast food.

    How I started IF:Cold turkey, just gave up eating for 24hr. I was very hard to go 24hrs however If I always had a good nutrient dense meal the day before I would be much better on the fast days. So when it was time to eat I would eat and enjoy the food and never pig out.

    Fast days:water, tea and coffee. unlimited amount

    Eat days:I consume approx 2000k day or less nutrient dense food

    Workout:walking/light gym push ups and sit ups

    Hope this helps anyone seeking the extra push to change over to this life change!

    Thanks again Todd for this awesome blog!!!!

    Retired fat guy!

    Reply
  11. Troy

    I’ve been practicing IF for 6 years now. I had no need for weight loss, but still, I noticed my body fat drop to about 8% (from about 12%).

    My eat schedule is:
    Full eat day
    Breakfast only (followed by a minimum 20 hour food break)
    Breakfast only
    Full day
    Breakfast
    Full day
    Breakfast

    I am 40 years old, and still a competitive athlete. My hard workouts are saved for eat days.

    I almost never feel hungry, enjoy a clear mind and good energy. I experienced no change in my multiple body aches, accumulated through years of banging my body around like a pool cueball.

    Cons:
    The first month, I was terribly grumpy/hungry. For many months, my hands were always cold. Last year, I had to stop for three months due to uncontrollable weight loss (though that last one wasn’t necessarily caused by IF).

    Funny to come across this site, since I stumbled upon it while researching my new adventure… daily cold showers.

    Reply
    • Todd

      Troy,

      Thanks for sharing your IF protocol. Looks mostly like an “ADF” (alternate day fasting) routine, similar to Brad Pilon’s Eat-Stop-Eat.

      Your observation about mental clarity rings true with my own experience, as well as what many others report.

      It’s interesting that you experienced cold hands. I’ve had this symptom, although not consistently. If I read your comment correctly, it sounds like your cold hand problem spontaneously resolved. Any thoughts as to why this happened?

      My most recent post deals with how the brain regulates metabolism, body temperature and other homeostatic variables. Perhaps the hypothalamus takes a few months to adjust to a change in eating like IF, and body temperature eventually returns to normal. Either than, or your body temperature drops and your thermoreceptors re-adjust your perception of cold!

      Todd

      Reply
      • Troy

        Todd,

        My own thoughts on my cold hands… I had taken away a regular source of heat production, as digestion produces a large amount of heat. It’s been awhile, but as I recall, they were only cold on “no eat” days.

        They were physically cold to the touch, and that went away, so my guess was that my body adapted by increasing my circulation to my hands.

        My average body temperature now, is 97.1 (compared to normal 98.6 prior). My blood pressure went from 130/95, to an average of about 106/66.

        Though, from what I’ve read, there are studies that show my style of eating, often results in an increase of blood pressure, which makes no sense to me. The lack of carbs, should result in a loss of water weight, thereby dropping your blood pressure.

        I am very curious to see how the cold showers affect my vitals. Wim Hof touts that your resting pulse should drop between 20 to 30 bpm, but he does spout off a lot of… well lets just say he says whatever is on his mind, and I don’t think he’s very familiar with the scientific method. But he’s a total rockstar, so I don’t hold it against him.

        Reply
  12. Deepak

    I started IF a few weeks back after reading your blog. I was interested in checking your videos out but it seems that they are private. Anyway I can view them? Thanks
    -Deepak

    Reply
    • Todd

      Deepak,

      Thanks for noticing this. I’ve gone back into YouTube and corrected the settings to allow public viewing of the videos. I hope you enjoy the talk and find it informative. Let me know if you have any questions or comments.

      Todd

      Reply
  13. When I first made the shift to intermittent fasting, I did notice a decrease in energy as I was consuming less carbs on my non-WO days. After the shift, I’ve noticed a mental clarity upon waking up. Also, I don’t have such a foggy haze, almost like i was waking up from a hangover.

    There is a huge increase in the amounts of protein you eat, which can be more expensive.

    Either way, the pros far outweigh the cons!

    Reply
  14. Thanks for the Intermittent Fasting video links – quite informative!

    Reply
  15. I’ll try to be brief… I’m about 6’1″ and have weighed @220 lbs for 5 years or so. Until recently was an avid runner – 20 miles/week. I could never understand why I couldn’t break the 220 lb barrier, but hopefully this will all change!

    I started IF about 2 weeks ago (daily fast-5 schedule) and so far have found it much easier than I thought and am very excited about the journey. I’m still running (slow jog), but decided to cut it way down to a measly mile or so, just to stay active and get my metabolism going so-to-speak. I have not lost any weight yet (slight body composition changes, though), but do hope that it’s my glycogen stores that have yet to be totally depleted – the way I understand this anyway.

    I’m a moderate alcohol drinker (2-3 rum/diet drinks in the evening). It’s strange that it’s not mentioned anywhere on this page (except for Todd’s reply about having drinks 2-3 days a week), but was wondering if alcohol hinders this process at all? Not necessarily weight loss (which I want to do as well), but the long term effects of the many fasting benefits? I consume the drinks in the 5 hour window, so I’m not “cheating” as far as the schedule is concerned. Was just basically wondering how alcohol might play a roll in all of this. Logically it would seem to slow the process down significantly, although it may not as I’ve read that it has little to no effect on insulin response, glucose levels, etc. Would love to hear some thoughts on this.

    Thank you for the inspiration, Todd!

    Reply
    • I have lost 100 pounds and never gave up drinking. Only walking and abs for my workout.

      Reply
    • Todd

      Ron,

      I’m glad to hear that IF has helped you break through your plateau, and also that you are being patient about weight loss. Regarding exercise, you might consider one small adjustment: punctuate your slow jog with occasion hard sprints of about 30 seconds. Or perhaps climbing a few hills that are steeper than you might have previously attempted. Get your heart ticking hard and get yourself out of breath — but only for about 30 seconds at a time. Then run slow again until you catch your breath. If you add 2 or 3 sprints into your otherwise steady slow jog, you may be surprised to find your body composition and overall metabolism showing some positive changes.

      Regarding alcohol: It does not DIRECTLY affect blood glucose. However, frequent and elevated alcohol consumption CAN cause insulin resistance, particularly hepatic insulin resistance. The amount and frequency of alcohol that leads to this consequence is most probably highly individual. Hence, see Scott’s comment above. In my case, cutting back from a daily drink to drinking twice a week made a significant difference.

      Todd

      Reply
      • Scott, Todd,

        Thanks much for your replies! I will take heed and cut back on my daily spirits – maybe keep it at weekends only. I’ve read conflicting information that alcohol “stops the fat burn process” until it’s eliminated – which may explain little to no weight loss thus far (hindering the entire fasting period?). Again, I will cut back at least until I reach my goal weight down the road.

        I will also add some occasional inclines to my jog (currently on a treadmill), makes perfect sense. I’m done running 4-5 miles daily as this did nothing for me apart from a good aerobic workout. I also noticed my blood pressure has decreased about 10 points; another benefit so far for me!

        Thanks again!

        Reply
  16. Another quick question: I drink a glass of water with a couple of tablespoons of a squeezed lemon in the AM. Never thought about this until now, but does this essentially “break the fast”? I realize lemon doesn’t have a lot of sugar/calories, but it does have some and was wondering if it’s enough to cause an insulin response and interrupt the fast.

    Reply
    • Todd

      Ron,

      I would not worry about the lemon water. As long as the calories are less than about 5 or 10 within a 3 or 4 hour period, you won’t break the fast. Coffee, tea, or herb tea without sugar are also fine.

      Todd

      Reply
  17. Thanks again, Todd. Great, life-changing info here!!

    Reply
  18. OK, more questions for this discussion.

    Have to admit, I love food! And yes, carbs are one of my weaknesses, although to lose a few pounds, I will restrict carbs if that’s what it takes.

    My initial question is, if my [current] goal is to lose weight, how much carbohydrates is too much (during a 5 hour eating window)? In other words, at what point would the carbs replenish the glycogen stores to the point that fasting is somewhat negated… say for the following day(s)? As I write this, I realize that this is probably variable per individual/energy used, etc., but should I be “counting carbs” to a point of limiting them to make this a more efficient process? Not really talking sugar here, but breads, crackers, pastas, potatoes. I don’t generally overdo it, but should you limit them at all?

    Reply
    • Todd

      Ron,

      I know there are people who calculate out the precise amounts of fats, proteins and carbs they need for this or that effect. I don’t take that approach because I look at the body not as a machine with precise fuel consumption ratios, but rather as a biological system under hormonal and neurological control. Especially important is the operation of your hypothalamus in the control of appetite and energy expenditure.

      Of course, energy must balance in the end, but far more important are the hormones that drive us to eat or be active, and that control the access and rate of utilization of fats and carbohydrates. Don’t waste your time counting grams of carbs or fats. But choose carbs and fats that resensitize your hypothalamus, renormalize your appetite, and rev up your metabolism. Bread and pasta is fine, but in very small and occasional doses. A better source of carbohydrate is vegetables, particularly of the non-starchy kind, particularly those rich in phytonutrients. Excellent fats are the shorter saturated fats (coconut oil, butter) and the DHA and EPA in fatty fish (eel, salmon).

      So don’t focus so much on the amount of carbs and you are eating, but rather the frequency and quality of those carbs and fats. Minimize inflammatory carbs and fats (e.g. fructose, palmitic acid, trans fats), eat them within a short window every day or two, and you’ll find yourself naturally limiting your consumption once you become more sensitive to insulin and leptin. Intermittent fasting and high intensity exercise will also sensitize the hypothalamus. You’ll also be allowing yourself to hang out in fat-burning mode more of the time.

      If all of this is suprising to you, I suggest reading my post called “Obesity starts in the brain“.

      Todd

      Reply
  19. Not surprising whatsoever, thanks!

    “Coffee, tea, or herb tea without sugar are also fine.”

    What about caffeine? I’ve noticed lately that it’s frowned upon in many diets today – with good reason? Do you still shy away? ( i.e., your previous link, http://www.ncbi.nlm.nih.gov/pubmed/11478588 )

    I’m in the process of reading the thread at sethroberts.net. Very interesting indeed.

    Reply
    • Todd

      Ron,

      I tend to drink decaffeinated teas and decaf coffee (both of which still contain some caffeine) mainly because I enjoy the flavor of coffee, yet the full-bodied coffees make me a bit wired. On occasion, I do drink full coffee — for example, when I travel overseas and need to re-set my body clock. But I don’t think caffeine is anything to worry about, especially if you don’t sweeten your caffeine drinks.

      The study you posted involves the co-administration of caffeine and sugar, in the form of an oral glucose tolerance test. Caffeine was ingested at a very high level – at the equivalent of about 5 cups of coffee in a single dose! (5 mg/kg for a 75 kg person = 375 mg. A cup of coffee contains about 75 mg caffeine). AND it was combined with 75 grams of glucose – the amount in about 6 chocolate chip cookies! So we learn that consuming 5 cups of coffee on top of the 6 cookies causes a 24% elevation in blood sugar. Not a huge surprise.

      Caffeine does raise insulin — temporarily — but it also temporarily raises epinephrine (adrenaline) and glucagon, which liberate glucose and fatty acids from your glycogen and fat stores. So long as you are not consuming a lot of sugar or fat at the same time, the caffeine is thus actually helping your energy levels while lose a little weight at the same time. As long as you drink it in moderation, and unsweetened, I think there is no harm and it is probably beneficial, as caffeine also helps sharpen cognition. The key is to keep those rises in stress hormones brief and limited to part of the day, so that your adrenal glands are stimulated intermittently, but have plenty of time to recover between exposures. Caffeine is mainly a problem only for heavy users.

      Reply
  20. Well shoot, I guess my 1 cup of black in the AM is OK then!

    Sorry for all of the tedious questions, just trying to maximize the benefits of IF. I’m seeing great results so far!

    Reply
  21. Ron

    Just to update, I’ve lost 15 pounds so far (@ 6 weeks) and feel great – smashing through my plateau! I cannot believe that more people don’t know about this.

    Another question, please.

    Glycogen stores; you have a graph in the video that indicates how much glycogen one [may] have. Is this “on average” in humans or does it depend on one’s size? In other words, would it take longer for an obese person to burn their glycogen stores before say, a person that’s 10-15 pounds over weight? For example, the Fast-5 docs say that it takes, on average, 2 weeks to deplete your glycogen (this is exactly what it took for me to start noticing weight loss). Would this be about the same for an obese person?

    Thanks again!

    Reply
    • Todd

      Ron,

      Congratulations on your excellent progress so far in breaking through your plateau!

      Glycogen stores do vary somewhat between larger and smaller individuals, but this is related more to your lean muscle mass and the size of your liver. So an active six foot tall man with a certain sized skeletal frame will have about the same amount of glycogen whether or not he is lean or obese. An obese sedentary person may even have less glycogen than a lean active person.

      In the big picture however, variation in fat stores is MUCH greater than variation in glycogen stores.

      Reply
      • Ron

        Thanks very much again, Todd!

        Reply
  22. Jenny

    Thank you Todd for the weath of information on this site. It is seriously changing my life.
    I have started reading Body by Science, began taking cold showers, and starting IFing Eat stop Eat 2x (24-hour fasts). And learning ALOT in the process.
    I need to lose about 50lbs and I am wondering how much weight do you think one would be able to lose per week using this natural tools and hormesis? Do you have any other tips you’d suggest to include? I love the idea of increasing my overall health naturally, and obviously would like to lose the weight quickly.

    Reply
    • Todd

      Jenny,

      I’m happy to hear that some of the ideas on this blog are helping. Losing 50 pounds for health is a great goal. My main advice is focus mainly on increasing lean muscle mass and insulin sensitivity, rather than on how quickly the scale moves. Your biggest struggle will probably be appetite, and I think the best way to tame appetite is via hormesis — the application of both physical and psychological “stress” to rewire the way you approach eating and exercise. Whereas slow or prolonged cardio workouts typically increase appetite, I’ve found that exercise that involves short intense bursts of effort, or other psycho-physical challenges like cold showers and IF, rebalance your hormones to reduce those which inhibit fat loss (like insulin and leptin) and activate those that engender fat burning. My Diet page has some suggestions regarding how to re-train your appetite through reconditioning of the insulin response to sensory cues.

      Don’t expect a steady loss of X pounds per week. You may go several weeks without noticing much change, then find that you suddenly drop 3 or 5 pounds in one week, before plateauing again for a few weeks. To get you through this, I have a few suggestions in my post “How to break through a plateau“.

      Best of luck,

      Todd

      Reply
  23. Ron

    Just another update on progress; been fasting daily since Apr 18. I’ve lost a little over 20 lbs now – about to crash through 200 lbs. Doc took me off BP Meds, my cholesterol went from 233 (Dec 2011) –> 183! Triglycerides: 110 –> 53. My blood glucose mid-morning was 76. In my life, I’ve never been below 215 cholesterol!

    I haven’t felt this good in a long time! Best of all, food freedom! Can’t thank you enough, Todd.

    Looking forward to more articles – been a while!!

    Reply
    • Todd

      Ron,

      That’s such good news! What I like about your comment especially is that you are keen about not mere weight loss, but the physical and mental health benefits of intermittent fasting. Now that I’ve been IF’ing for a few years, I can tell you that these benefits are deep and long lasting.

      Todd

      Reply
  24. Orly

    Hi,

    I’ve been doing intermittent fasting for the last 6 weeks and had great success with it. Combined with resistance training and HIIT, my body fat dropped from 16% to 14% without losing muscle mass. I was doing the leangains approach to IF which is 16 hrs fasting followed by 8 hrs of feeding.

    However, when I tried to check my fasted glucose level (around 18 hrs fasting), it was above the reference average, around 105. Is that normal? HBA1C is 5.2%. Doctor said that I might be glucose impaired.

    Another thing, I have been having problems getting enough sleep during the 5th and 6th week due to difficulty falling asleep. Any feedback on my experience is greatly appreciated.

    Reply
    • Todd

      Hi Orly,

      Glad to hear that you’ve had some success with IF and intensive exercise. It’s hard to make a judgement based upon a single fasting blood glucose reading. First, you’d want to know what your BG readings have been over the past several years, to know whether you are improving or not. Second, BG measurements can vary quite a bit based on time of day, last time exercising, emotions and other factors beyond just fasting. Buy yourself a cheap glucose meter and strips and do some experimentation on yourself to see what really affects your glucose readings.

      Here are a few links to look at:
      My own experience: http://boards.sethroberts.net/index.php?topic=7511.0
      The experience of a diabetic who cured himself using IF: http://shurie.com/lee/writing_defeat_diabetes.htm

      Your difficulty falling asleep may be due to elevated cortisol in the evening. Try taking a cool bath or doing some resistance exercise in the evening. Listen to some calming music. Or eat a small healthy snack an hour before bedtime.

      Todd

      Todd

      Reply
      • Orly

        Hi Todd,

        Thanks for the prompt reply.

        Last December, I got my BG tested too and it was 89, I was eating 6 times a day during that time with the same weight lifting and cardio regimen. Last April, BG was 95 wherein I started dabbling with IF. I stopped doing IF for a month due to vacation and recently got back on it and currently on my 6th week now.

        I really don’t know what’s happening. I am having success on my body recomposition but the sudden rise of my fasted BG is quite alarming. I am scheduled for another BG test today (FBS and PPBS)and hopefully things will be cleared out.

        Reply
        • Todd

          Orly,

          Blood glucose is sometimes not so straightforward. While an elevated BG can be a sign of pre-diabetes, when eating too much sugars or starches, it can be elevated briefly for two very different reasons: intense exercise and fasting. In these two cases, when insulin is suddenly reduced and glucagon and adrenaline are elevated, the liver is prompted to “dump” glucose into the bloodstream (gluconeogensis) to provide a ready source of energy. Glucose can also be dumped early in the morning upon waking — this is known as the dawn phenomenon. The combination of insulin reduction, increased glucagon/adrenaline, and glucose “dumping” could explain your sleep problems.

          In your case, particularly if you are burning fat and losing weight rapidly, you may experience transient increases in BG. The good news is that you appear to have a very efficient liver that is doing a great job of gluconeogenesis to convert your stored fat and glycogen to extra energy! You may want to slow things down and shorten your fasts. Instead of eating once a day, add a second meal or reduce the time between meals. If your BG is high in the morning, add a late evening snack to help prevent insulin from getting too low.

          Once one is adapted to more intense exercise or fasting on a regular basis, these fluctuations tend to stabilize. Your weight loss WILL eventually slow down, and your BG and sleep should normalize then. Give another 3-5 months, then re-test your BG. I’ll bet it goes down again. Then you’ll be more like the rest of us, and you will probably benefit by eating less frequently, without the side effects you are now seeing, which are probably a transient effect of rapid weight loss.

          Todd

          Reply
  25. Ron

    Probably a final update. I reached my goal weight early October – mid 180s – 35 pounds gone. I’m fasting only about 3-5 times a week now; seems to be about right to maintain.

    I’m also practicing low-carb and when I cheat and carb-up a little, wow!… the [water] weight really packs a punch. It can fluctuate up to 10 pounds or so in a couple of days. But alas, a couple of fasting days and I’m back to “normal”. Love the fact that I don’t have to stress about weight/basic health issues again.

    And Todd, I’d like your thoughts on the Nutrition Science Initiative (NuSI) when you have time.

    Reply
    • Jennifer Baker

      Hi there,
      Congrats on your achievement :) if you don’t mind asking, what style of fast did you go with? How often, and how many hours ect? Any tips or advise will be so appriciated. Thank you in advance.

      Reply
      • Ron

        Hi Jennifer,

        I adhered to the Fast-5 lifestyle (not truly 19/5 – more like 20/4). I was strict about it for about 2-3 months or so and dropped 20 pounds quickly (see my prior posts – http://gettingstronger.org/2011/05/intermittent-fasting-for-health-and-longevity/comment-page-1/#comment-14365). I still had more weight to lose, but didn’t need to be so aggressive about it any longer. I knew that I could lose the rest without the fear of failing as in the past; if that makes any sense. I started adding a noontime lunch here and a late lunch there, maybe a breakfast, etc. Adding the meals was no problem because you can start fasting again the very next day, picking up where you left off.

        I also reduced my carbohydrates tremendously (to less than 100g/day – this will vary with the individual). I strongly believe now that by just reducing your carbs alone, you can achieve your goals, whether it be weight loss, increased health or both. And like Todd has mentioned, I will continue to keep carbs at a minimum and occasionally have my cheat days just to keep the insulin machine guessing :) I could go on and on about the details & benefits…

        I could probably stand to lose a few more pounds, but I decided to take my time and reduce my fasting times more often (especially since the holidays are coming up AND my wife told me I was fine!) – complete food freedom! And, because I know now that, if I want to set a NYs resolution to lose say, 5 pounds, I know very well that I could do it fasting for about a month or so!

        Reply
    • Todd

      Ron,

      Great to hear of your success. Dropping 35 pounds is no mean feat; weight loss always requires discipline because it involves choices. But the combination of IF + low carb is a big help because not only does it suppress appetite, it improves insulin sensitivity. So it improves health and prospects for longevity (hence the title of this blog post).

      I’m very supportive of NuSI. I saw Peter Attia’s talk on cholesterol at the AHS 2012 meeting in Boston; he marshalled excellent evidence to demolish the current obsession with cholesterol as a risk factor for CVD. He and Gary Taubes are to be lauded for putting together a scientific research to rigorously determined what does and does not work in dietary approaches to weight loss. If they are as careful as I think they will be, the “low carb” vs. “low calorie” dispute will be put to a fair test. While I have a hunch about what they’ll find, good science often reveals surprises. So I’m eager to see what they find.

      Best regards,

      Todd

      Reply
      • Ron

        Thanks again, Todd.

        Yes, Dr. Attia’s cholesterol talk blew my mind! Who would have thought that [most] fat is good for you! Definitely a paradigm shift at its best. I too am looking forward to some of their results!

        Reply
  26. Jack

    Great series. Quick question – how long do you wait to eat after working out? Do you wait and let the HGH release continue or do you immediately to replace damaged muscle fibers with proteins?

    Thanks!
    Jack

    Reply
    • Todd

      Some believe that it is important to “refuel” within 30 minutes of a workout for maximum amino acid uptake and protein synthesis. However, I think that’s generally counterproductive because it quickly raises insulin levels, and shuts down the release of ketones and fatty acid release and their oxidation. I tend to follow Volek and Phinney on the benefits of extended fasting for some period after the workout. Their findings are that muscle is generally well preserved under ketosis for even several days of fasting. A post workout meal should be modest in size and moderate in protein.

      Reply
      • Jack

        Thanks for asking my question! So, about how long do you extend your fast for? An hour? Two? Also, if you are trying to build muscles, isn’t a insulin rush good, especially if you are on paleo/low carb meal or warrior diet? Why do suggest a post meal should be small and low in protein?

        Thx!

        Reply
        • Todd

          Jack,

          I originally followed Martin Berkans of Leangains in recommending a post workout meal high in protein and carbohydrates, within an hour of working out. But lately I’ve been persuaded by the research in Volek and Phinney’s book, “The Art and Science of Low Carbohydrate Performance“. They point out that, while it is true the rapid post-workout meals build muscle, they quickly raise insulin and blunt fat loss. (High protein also raises insulin so you have to keep it moderate. If you habitually delay eating and moderate the protein content (moderate is not the same as “low”), you will eventually become keto-adapted, which greatly improves the efficiency of amino acid uptake (especially for branched-chain amino acids like leucine). This sustains lean body mass.

          For more details, I suggest getting a copy of the Volek and Phinney book.

          Todd

          Reply
        • Jeremiah

          What are your thoughts about taking BCAA’s before and after workouts while fasting? Does taking BCAA’s affect your fast? Thanks.

          Reply
          • Todd

            Branched chain amino acids (leucine, isoleucine and valine) are anabolic and have been been used by weight lifters to build muscles. People take them as supplements, but they are abundant in meat and dairy – but also in seeds and legumes like cashews, almonds and the like.

            BCAAs induce a sharp insulin response, which will blunt fat burning, but not for as sustained a period as typical carbs. If you use them, I would take them at least an hour before working out, and not for several hours afterwards.

            Reply
  27. Jack

    Thanks!

    Reply
  28. Stephanie

    I’m so glad to have found your website, Todd. Using anti-corrective lenses, cold showers and your general philosophy have been wonderful. I love how dedicated you are to finding (and interpreting) research to support your ideas. I would love to reap the benefits of IF but I have some concerns. I’m 23 years old, 5’8″, under 120lbs and trying to gain weight. I’ve been diagnosed with adrenal fatigue and am pretty inflamed. I would like to reap the health benefits of IF but I would be very worried if I started loosing weight. Would the stress of eating less tell my body that it needs to store energy and encourage my adrenals to handle stress better? or would the stress likely be too much for someone with a history of adrenal fatigue? The Internet has plenty of information for how to loose weight but practically nothing for how to gain weight, and even less for how to gain it while using the principals you outline here. Any information you’ve unconvered or any ideas you have for how to apply these principles to my situation would be greatly appreciated. I want to get stronger and I think your philosophy holds a key.

    Reply
    • Todd

      Hi Stephanie,

      I’m glad to hear that some of the ideas on this site have resonated with you. Before suggesting any specifics, I would want to know more about the nature of your adrenal fatigue. Was this based on specific measurements of ACTH or cortisol levels? Are you experiencing chronic stress and poor sleep? Fasting, even intermittently, might exacerbate your problem until you first are able to improve your stress tolerance and improve sleep.

      Where to start? As general advice, since your adrenal glands are inflamed, I would start with eating a non-inflammatory “paleo” diet. You probably know all the good sites and books for this, but Art DeVany’s New Evolution Diet is a good start. Cut way back on sugars and carbohydrates other than fiber. So eat lots of protein and natural fats — from meats and fish, as well as fiber-rich vegetables (actually fruits) like avocados and olives, and from nuts. Minimize processed vegetable oils, which are high in inflammatory omega 6 fatty acids. Eat lots of green vegetables like broccoli, brussel sprouts, asparagus, kale, etc. Eat low glycemic berries like blueberries and strawberries.

      Second, what role does exercise play in your life? Over-exercise, particularly aerobic exercise, can lead to adrenal fatigue. A much better plan for you to reduce stress and gain weight is periodic resistance exercise. Have you tried weight lifting? Try a program that works on lifting the heaviest weights you can, slowly, with a small number of reps. Here is a good reference:

      http://www.amazon.com/Body-Science-Research-Program-Results/dp/0071597174

      You want to go for intense but short work outs, and follow these by eating protein rich meals or smoothies. This will have several benefits. First, building muscle mass will add the good kind of weight. More importantly, it will build physical strength and at the same time increase your stress tolerance. Muscle tissue is not just for strength — it is metabolically active and will help you to counteract inflammation, and help you combat stress.

      If you want to do cardio, go for intensity and fun (like kickboxing, steep hiking, mountain biking, climbing, etc.) rather than boring endurance, like treadmills.

      A lot of the advice out there for overcoming adrenal fatigue is misleading. For example, here is a reference that correctly emphasizes good nutrition, but suggests frequent eating and minimizing stress:

      http://www.naturalnews.com/019339.html

      The problem with this advice is that we can’t avoid stress in our lives! A much better plan is to immunize ourselves against the “bad” stress (chronic low level stress), by subjecting ourselves to brief spurts of deliberate voluntary stress — intense exercise, cold showers, and other physical challenges. If you experience stress intermittently, and make sure to get plenty of rest, relaxation and fun in your life, you’ll improve your overall stress tolerance. Deep, restful sleep is very important. The first sign that you are recovering will be the quality of your sleep and how rested you feel upon waking.

      Hope this helps give you some ideas.

      Todd

      Reply
  29. Todd,

    I am still trying to determine if coconut oil would interrupt autophagy. Opinion appears to be split on the issue. Thoughts?

    Many thanks

    Reply
    • Todd

      Thomas,

      I don’t know the answer to your question. Coconut oil contains negligible protein or carbohydrate, and its medium chain triglycerides are readily oxidized for energy. So it should not significantly inhibit autolysis. But you might take care to limit consumption of coconut oil to small and occasional doses. True fasting, in combination with exercise, is the most effective way to boost autophagy.

      Todd

      Reply
      • Thanks Todd, I assume by “take care” you mean in regards to autophagy and not consumption in general?

        Reply
        • Todd

          Thomas,

          Yes. I think coconut oil is a great addition to the diet, even in generous amounts. As you surmised, my point was only that if you want to maximize autophagy, then you should limit consumption of coconut oil (or any oil) to modest levels — a tablespoon or two, a few times a day. Autophagy will still occur on a high fat diet, but it will be muted compared with total fasting, or fasting plus exercise.

          Todd

          Reply
  30. Ann

    Thank you for this informative and insightful talk and for making it available online. Is the question and answer session also available on video? Thanks.

    Reply
    • Todd

      Ann,

      I did intend to put the Q&A online, but never got around to. I’ll see if I can locate the original footage and upload it.

      Todd

      Reply
      • Xthesinos

        Todd,

        first of all, thank you for the creation of this WordPress. It is the single most interesting article base that i have found on the internet concerning health.

        I would appreciate your input on the following paper which concludes that chronic intermittent fasting may be bad for insulin sensitivity and results in insulin receptor nitration and redox imbalance(in mice).

        CERQUEIRA, F.M. et al. Long-term intermittent feeding, but not caloric restriction, leads to redox imbalance, insulin receptor nitration, and glucose intolerance.

        Thank you for your time!

        Reply
        • Todd

          Xthesinos,

          Thanks very much for the reference. The Cerquiera paper is very well done and should be taken seriously. It presents an interesting challenge to those interested in IF. I plan to address the points that it raises in an upcoming post within the next 1-2 weeks. Stay tuned!

          Todd

          Reply
  31. Mars

    Hi Todd

    I couple of weeks ago after some blood tests i was told my fasting blood sugar was high, so i went off for a diabetes screen test. My glucose tolerance test went well (i was able to more than adequately get my blood glucose down within the 2 hour period) but my fasting reading was still a little high (6.1 mmol/L, whereas the max recommended here in Australia is 6.0 mmol/L). As such i was told i was ‘pre-diabetic’.

    First of all, i am unaware of what sort of measurement uncertainty is associated with these readings. But that aside, i was surprised. I am slim, with very little fat around my mid-rift. I am very diet conscious and have minimised my carbs (especially sugars and starches) for years. Also, i only drink alcohol moderately. I haven’t done a lot of vigorous exercisec for years, but have always gone for brisk walks of about 40 minutes 3 or 4 times per week. Though i do note that in the past i have experienced drowsiness after meals. Additionally, i rarely have more than two meals a day.

    I am guessing that since my glucose tolerance test went well, that i am not generally insulin resistant. Does the fact that my fasting glucose is high indicate that my liver alone is suffering from insulin resistance or is it possible that i simply have poor liver function?

    I am now embarking on IF by only eating within a 3 to 5 hour interval in the evening (between 3pm or 5pm and 8pm). Also i have essentially cut out all caffein and alcohol during the week (lest this aggravate the liver), though may have some, very moderately, on weekends.

    I am also now doing vigorous aerobic exercise each day, and going for daily vigorous walks. The aerobic exercise i am referring to is 20 seconds of vigorous activity (such as running on the spot) with a 20 second break, done 3 times, so a total of 1 minute of vigorous activity (as popularised by Dr Michael Mosley on TV, have you heard of it?).

    Incidently, do you have an opinion about caffein, in this context? I was considering decaf (i understand you have decaf yorself), but then i’m wondering if the chemicals used to process the stuff might be worse than the caffein.

    I’m not seeking personal medical advise. Just wanting your feedback with respect to general principles, in the context of what i describe.

    Anyway, i’ll sign off, lest i over stay my welcome! :-)

    Thanks, Mars

    Reply
    • Todd

      Hi Mars,

      Definitions of “pre-diabetic” seems to change with place and time. Some like the World Health Organization set the threshold at 6.1 mmol/L (110 mg/dL), the Amercian Diabetes Association sets it at 5.6 mmol/L (100 mg/dL); others go even lower. Years ago it was set significantly higher. The point is that there is no magic cutoff — it’s a continuum. Keep in mind that fasting glucose measurements can vary a lot with method, time of day and factors such as how recently you ate or exercised. Based on your GTT, I would not get too worried.

      Regardless of whether you are formally “pre diabetic” or not, your embarking on IF and vigorous exercise is a good idea in itself. If you are like me and many others, you’ll feel more energetic, with more balanced energy throughout the day. You might want to read this account for inspiration:
      http://shurie.com/lee/writing_defeat_diabetes.htm

      I think moderate caffeine consumption is beneficial, particularly for cognitive function. But it has a tolerating effect, so it is easy to get sucked into increasing consumption. Too much caffiene can have negative cognitive effects and adversely affect heart function. So I usually drink decaf, sometimes topping off with 10-20% fully caffeinated coffee. In fact, “decaf” still has some caffeine in it.

      I’m not too worried about the residual chemicals used in decaffeination. Big brands like Starbucks use the solvent dichloromethane to extract the coffee, but it is quite volatile and there is essentially no trace of the solvent that remains in the coffee. Even if there were, I’m not particularly chemo-phobic. But if you are worried, there are plenty of decafs made using the Swiss water process or supercritical carbon dioxide, both of which are absolutely non-toxic.
      http://www.swisswater.com/consumer/decaf-experience/coffee-everyone
      http://ineedcoffee.com/decaf-coffee-methods/

      Todd

      Reply
      • Bill

        Todd, thanks so much for the prompt reply.

        My main concern with my fasting glucose result is that i do not fit the usual profile of a pre-diabetic (and yes, i agree it’s perhaps an arbitrary designation). As i say, i am slim, have minimal fat around my midrift, diet conscious, have low blood pressure etc. So this made me wonder if perhaps it meant i had poor liver function, or some other issue. This is why i thought i should minimise caffein and alcohol, as i thought not burdening the liver might be prudent.

        If not, then i would not have a problem with having a cup of coffee a day (fully caffeinated) as i have no real tendency to suffer from ‘consumption creep’ (provided it does not seriously aggravate my tinnitus, which i’m still trying to work out).

        My fasting glucosse test was performed in the morning after fasting for about 13 or so hours.

        Any comments would be much appreciated. But regardless i aim to continue with my IF, and am now into my 3rd day and having no real problems with it.

        Thanks again, Mars

        Reply
        • Todd

          Mars,

          You seem to be in good health, so I would not worry too much about caffeine and alcohol in moderation. If you are concerned about your liver function, I would suggest getting your liver enzymes tested:
          http://www.livestrong.com/article/503663-high-liver-enzymes-high-blood-sugar/

          As you continue with IF, periodically test your blood glucose. You can do it yourself with an inexpensive glucometer from the pharmacy. I and others have found IF and regular exercise can be effective in reducing fasting blood glucose levels.

          Todd

          Reply
          • Mars

            Todd

            Well i’ve now been doing the If thing (fast 5) for a week, and i know it’s early days, but – WOW! I feel great, have more energy and a greater sense of wellness. I only wish i’d started years ago!

            I’m also losing weight, which doesn’t interest me much as i was already slim (now down to 65kg at a height of 1760mm).

            For the record, i am performing the diet 5 days a week (weekdays) and not worrying too much on weekends.

            Anyhow, as you suggested Todd, i called my medical clinic to see if they had measured my liver function at my recent routine blood tests. They had and the results were well within the “normal” range.

            So i’ve decided to relax my diet a little. I am now having a cup of full caffein black coffee (unsweetened of course) per day, during my fasting periods. I am also having a glass or two of wine most nights. But i generally avoid sugars and starches.

            I am relaxing this on weekends, when i will not be deliberately fasting. Tonight being Friday here in Melbourne, i am having chocolate for the first time in weeks, and it tastes pretty damn good! I will also have a beer or three on weekends, but not on weekdays (too much carb).

            My aim is to determine the effect of my IF routine on my various inidicators in 3 months time (blood glucose, cholesterol etc, plus sense of well being and energy levels). Depending on what results i get, then i shall consider reducing alcohol and caffein, and even weekend treats (hopefully not!).

            A final comment, particularly in light of Ron’s comments below, i too have noticed a reduction in mucous. For me this is very welcome, as i previously had a lot of night time mucous and often congestion in my right ear (which suffers from tinnitus). I suspect this has been assisted by the IF, but there is a chance it has been mainly driven by tge fact that i almost eliminated dairy from my diet a few weeks ago (ofcourse having black coffee instead of my beloved latté’s has assisted here).

            Anyhow, shall report my progress down the track.

            All the best and thank heavens for people like you and for the internet!

            Mars

            Reply
            • Todd

              Mars,

              You are a model of IF success! It’s great to hear your story, which I think will inspire others to make a dedicated effort at intermittent fasting. We’ll be interested to hear how your blood analysis comes back at the 3 month point, although I think people sometimes put too much emphasis on biomarkers at the expense of mood, energy and functional benefits like endurance in sports.

              Cheers,

              Todd

              Reply
  32. Hi Todd,

    Ron again (I’ve commented a few times).

    I’ve been fasting (not really IF’ing – a modified version of Fast-5/low carb) for about 2 years now. I lost my 35 stubborn pounds 5-6 months into the lifestyle and have kept it off ever since. I haven’t had any negative issues to speak of (mostly positive! — too many to list), until recently. The past couple of months, I’ve developed symptoms of “dry eye” in one eye. It started about 2-3 months ago and I truly thought nothing of it until I read this article – http://freetheanimal.com/2014/02/ketogenic-diets-news.html

    When you have time, I’d like your thoughts on it please. I too have the occasional elevated FBG (105-110) in the AM (not concerned about this at all). I also have the low triglycerides and the “runny nose”/excess mucous on occasion (mentioned as well, among other things). What startled me a tad in the article was the “alleged” connection between mucin deficiency and stomach cancer :O

    Do you think that the lack of glucose on a daily basis, especially adhering to a low carb lifestyle as well, could cause or contribute to a mucin deficiency?

    Would just like your expert opinion… at your convenience of course!

    Reply
    • Todd

      Hi Ron,

      As you know, the topic of if and how much dietary glucose is needed has been a hot topic in the paleosphere for several years running. On one side are those (Paul Jaminet, Richard Nikoley, Stephan Guyenet) arguing that some dietary glucose and certain starches are beneficial, for immune health, mucin production etc. On the other side are strict low carb (and moderate protein) advocates, most articulately represented by Ron Rosedale, who acknowledge the need for glucose, but insist that a “good” low carb diet (one without excess protein or omega-6 vegetable oils, and with adequate mineral intake) will ensure adequate glucose production and regulation via gluconeogenesis. One of the better “debates” on this topic is contained in these two exchanges:

      Rosedale, on Jimmy Moore’s blog (scroll down a bit to where his letter starts):
      http://livinlavidalowcarb.com/blog/more-safe-starches-stuff-and-why-ive-decided-not-to-test-them-on-myself/12068
      Jaminet’s response:
      http://perfecthealthdiet.com/2011/11/safe-starches-symposium-dr-ron-rosedale/

      Both make good points, yet I tend to give the edge to Rosedale. If you don’t consume glucose or carbs, your liver will make it from fats and protein. If you are healthy, you should be able to make enough mucin and immune cells. If that’s not the case, the problem is not the availability of glucose, it’s an impaired ability to utilize it to properly glycosylate tissues: “Glucose deficiency is not the same as glycosylation defects or deficiencies. Again, it is not a lack of glucose but signals that tell us what to do with it that are most critical.” He makes a great analogy between the regulation of glucose and that of calcium. Calcium supplements are not generally the answer to osteoporosis; rather, the problem is that hormonal imbalances, metabolic derangement, and lack of exercise mis-directs the proper absorption and assimilation of calcium into bone.

      So if it’s not glucose deficiency, what else could be causing dry eyes or low mucin? Rosedale mentions several possibilities, e.g. insufficient intake of magnesium, potassium and certain other nutrients that can be lost when insulin levels drop.

      However, I think both Jaminet and Rosedale make a critical error in focusing only on fasting glucose levels. This leaves out most of the day, and ignores the patterns of blood glucose fluctuation! Those of us who pursue IF have low blood glucose and insulin for much of the day, punctuated by occasional rises (if low carb) or even occasional spikes for those who are not strict low carbers, such as myself. Intermittent fasting with occasional carbs achieves the best of both worlds – low average glucose for most of the day, minimizing glycation risks, yet period bursts of glucose that can be used if the body needs that. Glycation damage tends to be temporary, since one is regularly entering autophagy, which breaks down glycated proteins and other damaged cellular “wastes”.

      Whether or not you think that some dietary glucose is necessary, I see no argument that one has to have it every day. On the flip side, I don’t think there is any argument that brief spikes in glucose are irreversibly harmful, so long as they are spaced out between periods of fasting that naturally recycle glycated tissues.

      Reply
      • 'Mash

        Food for thought again Todd, thanks.

        Reply
      • Thank you again, Todd, for your detailed response. Those links are fantastic reads, to say the least!

        I supplement quite well (IMO), and won’t bore you with the details but by process of elimination, one thing that I did halt a few months ago is vitamin C (I’ve been a proponent of taking vitamin C to aid in the cold/flu season – and haven’t had as much as a sniffle in a few years – not sure if it’s the C, fasting or both, but I digress). So I’ll try vitamin C again for a while and see if that helps. I don’t eat much fruit, etc.

        BTW, in the back of my mind, I’ve always pondered this:

        “We cannot be sure that there may not be negative health effects from severe carb restriction that will show up only after decades.”

        Well, so far they have not been found. That is why carbohydrates are a nonessential nutrient.

        “I think everyone should acknowledge that very low-carb diets may have unexplored risks.”

        We can say that about any diet, and in fact any event. One can only use the best science available and make the best guess available. We do know one thing for sure, a high carbohydrate diet is a major cause of all chronic disease. I see nothing wrong in running the other way.

        I think he put that perfectly!

        >>>… I don’t think there is any argument that brief spikes in glucose are irreversibly harmful, so long as they are spaced out between periods of fasting that naturally recycle glycated tissues.

        Thanks for the reassurance… I myself am just low carb (with cheat days here and there) as opposed to no carb. And even Rosedale admits (paraphrasing) “one cannot sustain a strict zero carb lifestyle.”

        As a matter of fact, I personally think it would be quite impossible for anyone to maintain for long periods of time, let alone forever. Besides, we have to “live” occasionally. And, as you’ve alluded to previously, it keeps the body’s mechanisms guessing.

        Reply

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