Archive for the ‘Diet’ Category

Obesity starts in the brain

66 Comments
Posted 25 Nov 2011 — by Todd
Category Diet, Health, Psychology

 

Where does obesity begin?  What drives you to eat too much or expend too little energy, and why has there been such a dramatic increase in obesity since 1980? Some recently popular explanations are the carbohydrate / insulin hypothesis (CIH), singling out the prevalence of carbohydrates in the diet, and the food reward hypothesis (FRH), putting the primary blame on the availability of “hyper-palatable” food.

In this post I will present evidence for new paradigm, which I call the  Hypothalamic Hypothesis (HH).  I think it provides a better explanation for the facts of obesity than the CIH and FRH theories, and leads to some different advice about how best to lose weight.

Some recent research suggests that obesity starts with specific physical changes to the brain. Appetite is regulated by the hypothalamus, particularly the arcuate nucleus (ARC), ventromedial hypothalamus (VMH) and lateral hypothalamus (LH). It turns out that two very specific changes to the brain cause us to get get hungry, overeat, burn less fat, and gain weight. And these changes to particular brain structures come about as a result of what you eat, eating frequency, and to some extent your activity level. The problem of obesity or overweight is often portrayed as a single problem, but it is really two problems, and each type of obesity corresponds to one type of brain alteration. Failure to distinguish these two types of obesity has resulted in much confusion. In part, the confusion comes about because these two types of obesity frequently occur together in the same individual, although one type is usually dominant. If you understand this, and you understand the role your brain plays, you can become more successful at losing excess weight.

I’ll spend a little time explaining the theory, provide some specific suggestions for how it can help you fine tune your weight loss program, and try to point out why I think the Hypothalamic Hypothesis overcomes some weaknesses of the other obesity theories.

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Does tasty food make us fat?

15 Comments
Posted 09 Sep 2011 — by Todd
Category Diet, Psychology

Are we getting fatter because there is just a lot more irresistibly delicious food around us?  Does that explain the obesity crisis?

That theory has been around the block but it is in fashion again.   In 2009, David Kessler’s book, “The End of Overeating” put forward the thesis that food in contemporary American food has been deliberately engineered–by adding fat, sugar and salt–to exploit our neurochemistry and hijack our free will.

More recently, one of the luminaries of the Paleo movement, Stephan Guyenet, has formulated his own version of this theory, in a compelling series on his Whole Health Source blog, arguing that  ”food reward” is a main driver of obesity. His prescription:  eat a bland diet. Guyenet’s talk about this at the Ancestral Health Symposium last month is the buzz of the paleosphere.

But I think the theory is wrong, for the simple reason that it too blindly takes correlation for causation. And in doing so, it gets the causal direction mostly wrong. We don’t get fat because food has become too tasty. Rather, to a large extent, it is the metabolism and dietary habits of the obese that make food taste too good to resist, leading to insatiable appetites. And the good news is that we are not consigned to blandness.  If we eat and exercise sensibly, we can eat flavorful, delicious foods and enjoy life, without packing on the pounds.

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Get stronger using stress oscillation

9 Comments
Posted 14 Aug 2011 — by Todd
Category Diet, Fitness, Health, Hormesis

How much weight lifting or other exercise is optimal for fitness?  What is the right amount of carbohydrate restriction or fasting for sustained weight loss and health? What level of exposure to allergens will reduce allergies? How many hours of sun tanning is healthy? How frequently should plus lenses be worn to reduce myopia?  Do I need to take cold showers every day to get their benefit? How much stress is enough — and how much is too much?

Many of the questions I get on this website and the forums are of this type.  People understand the general concept of hormesis, namely that exposure to controlled amounts of stress can be beneficial, because it elicits beneficial adaptive responses in the organism.  They understand that weight lifting builds muscles, and that intermittent fasting and calorie reduction can be healthful. But too much of any stressor — weight lifting, caloric restriction, sunlight, allergens  – can have adverse consequences.  With hormesis, it seems, the Goldilocks principle applies: to get a benefit, the level of stress must be “just right”.  And because it’s so easy to veer into overload, many people seek to avoid even mild stress:  Avoid allergens. Cover up with sunscreen. Eat frequent small meals. Don’t exert yourself. But if you choose this path, you forgo the possible hormetic benefits.

So how do you determine the optimum level and frequency of exposure to a stress?  And how much rest or recovery between exposures is optimal? Read More

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Intermittent fasting for health and longevity

46 Comments
Posted 28 May 2011 — by Todd
Category Diet, Health, Hormesis

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.

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My upcoming talk on intermittent fasting

7 Comments
Posted 24 Apr 2011 — by Todd
Category Diet, Health

Those of you who live in the San Francisco Bay Area may be interested in attending a talk I’ve been invited to give on May 18 in Palo Alto.  The topic is “Intermittent fasting for health and longevity”, and I plan to summarize both the recent science and the best practices for successful fasting.

 

UPDATE: A video of this talk is now posted HERE.

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The case against antioxidants

28 Comments
Posted 13 Mar 2011 — by Todd
Category Diet, Health, Hormesis

Antioxidant supplements are probably ineffective.  They may even be hazardous to your health.

Many people take daily supplements that include antioxidants such as Vitamins A, C, and E; beta carotene, coenzyme Q10, and alpha lipoic acid. I used to be one of them, convinced of the theory that supplementation with antioxidants is an effective way to neutralize harmful free radicals.  These free radicals, also called ROS or “reactive oxygen species”, can cause oxidative damage to cells and organs, and have been implicated in the pathogenesis of degenerative diseases such as cancer, heart disease, and Alzheimer’ disease.

However, study after study not only fails to show a consistent benefit, but in many cases documents positive harm from taking antioxidants. While I continue to believe that antioxidant supplementation is helpful in certain isolated cases of acute infection, tissue damage, or a damaged or aged metabolism, for most of us antioxidants are probably worthless. In fact, antioxidant supplements can interfere with and weaken the body’s inherent ability to mount an effective defense against oxidative damage and its contribution toward degenerative diseases.

I’ve resisted this conclusion because I could not make sense of it.  That is…until I came across recent research into the biochemistry and genetic regulation of the antioxidant response element (ARE). Fortunately the ARE provides us with an in-built adaptive stress response that combats oxidative stress and inflammation The ARE makes the need for antioxidants in the diet unnecessary — other than to keep our food fresh. Surprisingly, antioxidant supplements can impair our adaptive stress response.  But there’s much we can do to strengthen this response. Read More

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Does insulin make you fat?

57 Comments
Posted 03 Feb 2011 — by Todd
Category Diet

Whether or not insulin is to blame for the obesity epidemic is one of the hot questions being debated on heath and diet blogs.  On the surface, this seems like an arcane question that would mainly interest physiologists and diet researchers.  After all, who really cares about the underlying mechanisms of fat storage and release?   Most of us just want to know some practical steps we can take to lose excess weight and keep it off and, beyond that, to stay healthy.

It seems like a simple yes-or-no question of fact that you could settle by studying populations and doing lab studies. But it’s not so much a question about facts as one about causation.  Questions of causation are often the thorniest ones. This particular question has taken on almost political or religious overtones, provoking emotion and acrimony in the diet blogosphere. On one side are defenders of the Carbohydrate/Insulin Hypothesis, like Gary Taubes and Michael Eades.  This is laid out in detail in Taubes’ book  Good Calories, Bad Calories (2007), and more compactly in “Why We Get Fat: And What To Do About It” (2010). On the other side are opponents such as James Krieger and CarbSane, who find the Carbohydrate/Insulin Hypothesis to be oversimplified and deeply flawed, citing recent scientific advances. People tend to chose up sides in this debate.  I’ve been participating in this debate myself (while still learning a lot) on the websites of Jimmy Moore, James Krieger, and CarbSane. I won’t rehash all the technical details here. Instead, I’d like to propose a “frameshift” that recognizes and integrates the strong points from each side, attempting to overcome their shortcomings.

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Willpower: How to get it

3 Comments
Posted 16 Dec 2010 — by Todd
Category Diet, Psychology, Uncategorized

This week I wrote a guest post about willpower for Julien Smith’s blog.  It synthesizes a number of the ideas on this blog about deconditioning urges and emotions that tend to undermine our resolve to make significant changes in life.

Learning to fast

12 Comments
Posted 20 Nov 2010 — by Todd
Category Diet, Hormesis

I’m writing this post the week before Thanksgiving, to give you something to think about as you are polishing off that last piece of pie….

One of the most common reactions I get to my advice to try intermittent fasting is:  I could never do that!

Like the Jackson Browne song “Running on Empty,” the word “fasting” often conjures up dire images of starvation and energy deprivation.  Many of you reading this post may have experienced strong hunger pangs, headaches, tiredness, sweating and even shaking or wooziness when going without eating for even part of a day, much less a whole day.  So it is natural to extrapolate such experiences into the thought that going without food for a day, or even several hours, would invariably lead to uncomfortable or even dangerous hypoglycermic symptoms. That, together with the negative image of fasting as something unhealthy or associated with eating disorders, leaves most people pale at the thought of even attempting a short fast.

But I tell you, if you don’t try fasting you are missing out on an enjoyable, incredibly energizing experience that will put you in control of your eating and improve your health, your energy and your outlook.  Many people, myself included, have learned to fast for up to a day or even longer, on a regular basis and without negative repurcussions. Done correctly, short-term fasting is not dangerous, it’s actually health-promoting and greatly helps to retrain your appetite.  If you need to lose weight, the fast helps both in reducing basal insulin and retraining your appetite to be smaller. I’ve written about the benefits of intermittent fasting extensively on this site. Many of the Diet Links listed in the right-hand panel, such as fast-5 and Eat-Stop-Eat, amply document the safety and health benefits of fasting, dispelling the myths about “starvation mode”, slowing of metabolism,  and loss of lean muscle mass.  So I won’t reiterate here the voluminous evidence supporting the benefits of intermittent fasting.  Our bodies are designed to last many days with out food, without great discomfort, and in fact it is beneficial to our health to forgo food periodically. But many of you are asking: Am I really up to this?  How do I get started? Read More

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Change your receptors, change your set point

19 Comments
Posted 25 Oct 2010 — by Todd
Category Diet, Fitness, Hormesis

Why is it so hard to make permanent changes to your habits, your health, and your happiness?  Some of the most difficult struggles in life involve losing weight (and keeping it off), overcoming addictions, and recovering from depression. Many diets and therapies deliver great short term results, but the most common pattern appears to be relapse.  It often seems that you are destined to fulfill some biological program — that you are stuck with a high body weight set point or an addictive or depressive personality that cannot be escaped in the long run.

This pessimistic message is prevalent among those who have investigated the track records of the “helping” industries: the weight loss companies, the addiction recovery centers, and the various schools of psychology and psychiatry. Unlike the advocates, those who investigate them often find the results are less than what the practitioners might want you to believe.  In the arena of dieting and weight loss, books such as “The Dieter’s Dilemma” (Bennett and Gurin, 1982), and  ”Rethinking Thin”  (Kolata, 2008) echo the original set point theory first propounded by Gordon C. Kennedy in the 1950s; they conclude that your body weight is largely predetermined by a biological set point that is handed to you at birth, plus or minus about ten pounds. I do agree that sustained weight loss cannot be achieved through sheer will power alone, or simply by using diet and exercise in order to create a calorie deficit. Yet, while there is some plausibility to the set point theory, I am convinced that it is wrong because it overlooks some important factors. I’ve already given some of my reasons for my disagreement with set point theory in other posts on this blog (Flavor control diets, How to break through a plateau). But in this post I’ll present some strong evidence for an alternative theory, based on the homeostatic regulation of cellular receptors for hormones and neurotransmitters. This is a variable set point theory which I call the receptor control theory. This theory proposes a mechanism that controls appetite and body weight, as well as regulating the balance of  energy and pleasure in your life. It provides practical tools to lose weight and keep it off, overcome addictions without relapse, and move out of depression into happiness.

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