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.
When does stress help you and when does it hurt you? There is no doubt that stresses of the wrong sort can lead to anxiety, emotional turmoil — and eventually depression and diseases like atherosclerosis and cancer. Yet a central theme of this blog is that certain stresses are “hormetic”: at the right dose and frequency, stress can actually make you stronger and more resilient. The many posts on this blog illustrate how stress can be channelled to build muscle, retrain appetite, improve eyesight, strengthen immunity, defeat allergies, and tame addictions and anger. Judicious exposure to stress can even promote joy and excellent health.
But one can come away from the study of hormesis with the misleading impression that it’s all about adjusting the level and timing of stressors to induce an appropriate adaptive or defensive response. In this article, I would like to focus on a frequently overlooked ingredient in hormesis: the role of intention, attitude and voluntary choice. If you omit this ingredient, you are leaving out an important element of the way that stress helps you become stronger.
Voluntary, deliberate exposure to stress can be particularly effective in providing psychological benefits, including overcoming anxieties, obsessions and phobias, and vanquishing appetite cravings, addictions. Beyond overcoming such self-defeating tendencies, deliberate exposure works to unleash confidence and generate a sense of joy and accomplishment.
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.
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
Do you have trouble getting to sleep at night or staying asleep? About 30% of the adult population reports difficulties initiating sleep, sustaining sleep, or experiencing restful sleep. To deal with these problems, many people resort to medications or some form of supplement. But it now appears that there is an effective way to banish insomnia without the use of chemicals, by simply applying the principles of 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.
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.
Do you have allergies? Are you sensitive to certain foods or chemicals? If so, you are part of an epidemic explosion in the incidence of allergies and sensitivities in the U.S. and Western societies. The allergy epidemic is frequently blamed on the profusion of pollutants and toxic man-made chemicals in modern industrial society. And the conventional medical approach to dealing with allergies is to avoid exposure to allergens, and to block allergic reactions by using antihistamines.
But there is an alternative explanation and a more effective treatment, consistent with the theory of hormesis. The explanation is called the hygiene hypothesis and the treatment is called allergen immunotherapy. I’ll discuss these both shortly, but first let’s look at what is really behind the outbreak of allergies in the modern world. Read More