There is increasing evidence from recent human and animal studies that intermittent fasting — refraining from food or caloric beverages for at least 12 hours a day, several days a week — reduces the risks of cardiovascular disease, dementia and cancer. Those benefits are well-documented in the hyperlinked articles, so I won’t repeat them here. Yet many nutritionists hold that skipping breakfast or other meals and snacks can lead to weight gain and metabolic imbalance. Several recent articles have suggested that IF and breakfast skipping is a particularly bad idea for women. Much to my chagrin, this view been even embraced recently by a number of ‘Paleo’ advocates whom I respect, such as Chris Kresser and Mark Sisson.
In this post I’d like to address three main objections that have been raised against skipping breakfast and other forms of intermittent fasting:
- It spurs hunger cravings, leading to compensatory overeating and obesity
- It causes cardiovascular disease and metabolic dysregulation of blood glucose and hormone levels
- It’s bad for women, leading to hormone imbalance, disrupted menstrual cycle, and heightened stress response
I believe these concerns with breakfast skipping are overblown, based on an incorrect interpretation of a few animal and human studies, and flawed personal implementation. To the contrary, adaptation to meal skipping can actually help boost stress tolerance and improve blood sugar control. If practiced correctly, intermittent fasting (IF) can actually be a powerful tool to overcome hypoglycemic symptoms, and regain control over a harried lifestyle. And it can be particularly useful for women who are struggling with cravings, weight management and stress management.
Opposition to intermittent fasting arises from both published research and anecdotal reports. I’d like to address both in this post. I’ll first point out some significant flaws in the interpretation of several recent studies purporting to show negative effects of reduced meal frequency on women and other groups. And I’ll end by pointing out how to avoid common mistakes made by many who try intermittent fasting find it to be unpleasant and unsustainable.
Approached correctly, IF can provide major health benefits for most us.
Here is the video and slide set from my presentation at the Ancestral Health Symposium, August 9, 2014, in Berkeley, California. I enjoyed meeting many of you who were at the conference. I’d recommend watching the video first, and perhaps follow along with the uploaded slide set in a separate window, since it is more convenient for viewing references and other details.
(Note: You’ll notice some minor differences in the video and slide versions, as the AV team inadvertently projected an earlier draft rather then the final slides I had provided).
Overview of the talk. For ease of reference, here is slide-by-slide “table-of-contents” summary of the presentation. People are always asking to provide a detailed explanation of exactly what steps to take to improve their vision. You’ll find this bottom line “practical advice” in Slides 23-36
- Title: Myopia: a modern yet reversible disease
- My story: I wore glasses from Grade 10 until 15 years ago. I don’t wear glasses any more!
- To reverse myopia, we need to first understand the causes.
- Myopia defined. Myopia can lead to serious problems like cataracts and macular degeneration
- The prevalence of myopia has increased by 50-100% since 1970, across all age groups in the U.S.
- There is evidence for both genetic and environmental causes.
- An 1883 study of military recruits found myopia was much higher in students and merchants than farmers
- A 1969 study of Eskimos found that myopia had increased dramatically since Western schooling was introduced
- A 2012 study of German students found more than 50% of university graduates had myopia vs. 25% for dropouts
- In countries like Singapore and Taiwan, myopia is common among even young school children
- There is evidence that certain genes predispose to severe myopia. Copper deficiency induces myopia due to increased scleral wall elasticity.
- Cordain found that a high carbohydrate diet and deficiency of EFAs and minerals promote myopia
- It appears that a myopiagenic environment (near work) is needed to activate genetic predisposition to myopia
- What is the biological mechanism?
- The normal lens changes shape to focus
- Myopia progresses in two stages: (1) near work induces lens spasm, causing pseudo-myopia; (2) use of minus lenses temporarily improves distance vision, but leads to eye elongation and axial myopia. The result of elongation is a need to prescribe stronger minus lenses, in a vicious cycle of ever stronger lenses.
- Eye elongation is explained by the incremental retinal defocus theory. Retinal defocus causes release of neuromodulators that lead to decreased scleral tissue integrity, and axial growth
- The IRD theory has been proven empirically in chicks, monkeys and humans using optical reflectometry
- How can myopia be reversed?
- First, it is useful to understand the framework of hormesis — the beneficial response to low dose stress
- Weight lifting is a good example of hormesis and the principle of Specific Adaptation to Imposed Demand
- What if gyms had the same business model as optometrists? They would prescribe exoskeletons to help us walk, but these “crutches” would make us weaker, not stronger. Lenses are crutches
- To reverse myopia with hormesis, we need to use active focus. That means print pushing and plus lenses while reading, and progressively weaker minus lenses and image fusing for distance activities
- To embark on this journey, you must first determine how myopic you are, using a Snellen chart
- For print pushing, you need plus lenses only if your myopia is less than -2D. Otherwise use your naked eye
- Find the distance (D1) where print is at the edge of focus and (D2) where it starts to blur. Read between D1 and D2
- Move back from your computer or book to stay between D1 and D2. Do this for 2-4 hours a day, taking frequent breaks. Graduate to stronger plus lenses when you drop below 2D, and continue until you achieve 20/20 vision!
- For distance (walking, TV, movies, meetings) buy glasses with a 0.5D reduced prescription
- Once your vision gets better, you may notice “double vision” or ghosting. This is a good sign and something you can use to improve your vision!
- Find distant objects with sharp contrasting edges: telephone wires, tree branches, edges of buildings or signs
- Focus on the darker of the double image and away from the fainter image. With time, the darker image will become darker, and the fainter image will fade away
- Eventually the double image with fuse into a single crisp image — very exciting!
- Most people have a weak eye and a stronger eye with less myopia. The stronger eye will dominate, so strengthen the weaker eye by patching, shielding or winking shut the stronger eye…until the two eyes are roughly even.
- Frequently asked questions
- How much time should I spend on print pushing? Spend 2-4 hours a day while doing routine computer work or reading. This is not a separate exercise, but something you build into daily activity
- How long before my vision improves? Be patient — it’s like exercise or diet and won’t work overnight. Expect some improvement within a few weeks, but it may take a year or more to clear your vision
- Is this the same as the Bates method? Bates had some incorrect ideas about focusing, but his relaxation techniques can help reduce ciliary strain on the lens (pseduomyopia). However, his method does not help if you have axial myopia and spend a lot of time at the computer or reading. Print pushing specifically helps with that.
- Does active focus really work? Check out my blog and forum for success stories
- And for the skeptical, here is a page of references on the epidemiology and causation of myopia
- And more references on methods and websites that provide a similar approach to mine
- Your eyes are adaptive organs which allowed them to become myopic, but you can use that same adaptability to reverse the process using active focus for both near and far activities
- Rediscover your natural vision — make it fun, make it a habit, make it a game. You only have your glasses to lose!
Also be sure to check out these related posts and discussions:
There’s a surprisingly simple but little-known technique for measuring your in-the-moment ability to handle physical, mental and emotional stress. Some of us have a higher level of “adaptive reserves” than others. And for all of us, these adaptive reserves increase or decrease throughout the day and over days or weeks. You might have a rough, intuitive sense of when you are more resilient to stress, and when you are weak or more vulnerable. There is no shortage of advice on the Internet about “stress management”, fitness and diet. In general, sleep, physical activity and a nutritious diet build adaptive reserves, while these reserves are easily depleted by chronic stressors like worry or overwork.
But how do you know what really works to improve your resilience and resistance to physical and psychic stressors? How can you learn what diet, exercise, and activities actually work for YOU — not just what researchers, health professionals, bloggers or your friends claim should work?
What if I told you that there is a reasonably objective metric for your overall adaptive reserves and a simple, inexpensive, and noninvasive way to measure your adaptive reserves throughout the day.
The metric is called heart rate variability, or HRV. It can be measured in less than a minute, using an inexpensive chest strap or finger sensor, and any of several smart phone apps that can be downloaded for a few dollars. Based on a review of numerous studies and extensive personal experimentation, I’ve learned some surprising things about what tends to raise or lower HRV. And I’ve found one few amazingly quick, effective, and to boost a low HRV and keep it up, with real impact on adaptive reserves. (For the impatient, scroll to bottom of this post and read Recommendation #1).
I was saddened last month to learn of the untimely death of my friend Seth Roberts, a highly original thinker on matters that lie at the intersection of psychology and physiology Seth was known to many as a pioneer in the burgeoning field of self-experimentation. He was an early contributor to the Quantified Self movement, which owes a huge debt to his thinking. His experiments looked at how to optimize weight loss, mood, sleep, mental speed, balance and even to address specific conditions like acne. He wrote a blog on topics related to health and scientific method. I greatly enjoyed side discussions with Seth at the Ancestral Health Symposium meetings and personal correspondence over the years. This August, both Seth and I were scheduled to talk at AHS in Berkeley. While my talk on myopia will still happen, we will never hear his talk about self-experimentation.
Yet, to pigeonhole Seth as a primarily a self-experimentalist fails to understand what he was really about as a thinker. As a professional research psychologist, he focused on developing “productive explanations” — explanations that help us not only to make sense of an individual surprising observation, but that also make predictions about additional diverse and often novel practical applications. Self-experimentation was one important input, but certainly not his only source of experimental material. Self-experimentation has the virtue of allowing one to do more experiments in less time without spending a lot of money. Self experiments allow you to make incremental progress rapidly, to adjust and learn quickly.
But Seth didn’t stop there He typically synthesized results from many different fields into a coherent explanation. He was not against using data from larger experiments, even controlled double-blind experiments. It’s just that large “designed” experiments sometimes become unwieldy and expensive failures. Simple self-experiments get you started “learning by doing” and often allow you to make rapid progress and weed out untenable hypotheses quickly, before you sink a lot of time and effort into your investigations. The best example of how Seth combined self-experiment with classical science may be how he came up with the Shangri-La Diet, a seemingly wacky–but actually very effective–way of losing weight, safely and without hunger.
Much of the traffic to this blog comes from followers who have linked to blog articles that they like here. So I’ve just launched a Facebook page where I’ll frequently add links to interesting articles, post comments and questions, and generally encourage discussion on topics related to hormesis, such as diet, fitness, vision improvement, immune enhancement, psychology and even Stoicism.
The first linked article on the Facebook page relates to cold exposure and improve immunity. Check it out!
Let me know what you think about this…and please follow on Facebook using the link in the right margin, or just by clicking this hyperlink:
Click here for Facebook page
Listen to this inspirational TED talk by Stanford psychologist Kelly McGonigal. In my earlier post on Voluntary Stress, I wrote about the importance of attitude in how the body and mind respond to stress. McGonigal’s presentation here makes a nice connection between the psychology and the hormonal physiology of stress. Towards the end of the talk there is a very interesting discussion of oxytocin and the social dimension of the successful stress response.
Thanks to Tony Kiel and Marnia Robinson for each making me aware of this great talk.
Here is a hyperlink with slides from the talk I gave today at the Ancestral Health Symposium 2013 in Atlanta. I will upload a video of the talk once the organizers make it available. Until then, you can click on the “Link to audio recording” to listen to a recording that one of the conference attendees made and posted on YouTube. The sound is a bit faint, but still audible, and should make the slides more intelligible.
This presentation is based on material from several previous blog posts
The talk includes some new material not covered in those previous posts, in particular addressing antioxidant recycling, supplementation of calcium and the essential fatty acids EPA and DHA. I have also provided a list of references of supporting studies and literature in the final 3 slides.
I enjoyed meeting many new faces and recognizing old ones at this year’s AHS.
Hormesis is the ability of organisms to become stronger when exposed to low-dose stress. Is hormesis a basic principle of biology — or is it merely a strange but unimportant quirk of nature that only applies in exceptional circumstances?
Nassim Nicholas Taleb–the options trader turned philosopher–is intrigued by hormesis, and sees it as but one example of a much broader phenomenon: a fundamental principle he calls “antifragility”. The principle of antifragility applies not just to biology–but to sociology, economics, and perhaps even physics. Taleb has been developing this idea for a number of years. Antifragility made a subdued appearance in his 2007 blockbuster work, The Black Swan, a guide to dealing with unpredictable yet momentously consequential events in our increasingly volatile world. Taleb has now more fully developed the concept of antifragility in his most recent book, Antifragile: Things That Gain from Disorder.
The antifragile is the antithesis of the fragile. You might suppose that the opposite of “fragile” is something like “robust” — something that resists change. But Taleb points out that that would be the wrong answer. A fragile thing – a package of wine glasses, perhaps — is easily broken when subjected to a stressor, such as being dropped. Something robust is merely resistant to breakage. But an antifragile object actually benefits by being subjected to stress. Taleb conjures up an image of the fragile as an object we would ship in a box marked “Handle with Care”; by contrast, a box holding the antifragile would be labelled “Please Mishandle”
At first, this seems to be a tease. Are there really such antifragile things? Yes, indeed; the world is full of them, including you and me. And there are steps we can take to become ever more antifragile.