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.
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.
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
Want to experience the benefits of hormesis very directly? Take a cold shower! And don’t just try it once, make it a habit and take cold showers daily. I have been doing it daily for the past six months and am loving it!
As one form of hydrotherapy, the health benefits of cold water therapy are numerous. Cold showers provide a gentle form of stress that leads to thermogenesis (internal generation of body heat), turning on the body’s adaptive repair systems to strengthen immunity, enhance pain and stress tolerance, and ward off depression, overcome chronic fatigue syndrome, stop hair loss, and stimulate anti-tumor responses.
A number of recent weight loss methods have been developed that explicitly recognize a close relationship between flavor and appetite. These methods include:
- Flavor-calorie dissociation as advocated by Seth Roberts in his Shangri-La Diet
- Sensory-specific satiety, as advocated in David Katz’s Flavor Point Diet
- Tastants, another approach to sensory-specific satiety, as advertised in Alan Hirsch’s Sensa Weight-Loss Program.
- Odor inhalers, a third approach based on sensory-specific satiety, as described in Alan Hirsch’s book Scentsational Weight Loss, and marketed by him as “diet pens” offered by SlimScents
At first, some of these approaches appear to be mutually incompatible. The Shangri-La theory argues that strong or familiar flavors enhance appetite when they become associated with caloric foods. The other three approaches, by contrast, claim that intense flavors or aromas suppress appetite, based upon the principle of “sensory-specific satiety”, whereby an increase in the intensity of a single flavor or odor induces satiety. However, on closer examination, all of the above theories are consistent with one another, as I will try to show. Furthermore, they each provide some useful clues about how to achieve a long term weight loss and relief from hunger cravings by paying attention to the role of flavor and other food cues. Finally, as I will attempt to persuade you, only one of the above diets is truly a type of Deconditioning Diet that can lead to long term, permanent reduction in appetite, based on the principles of Hormetism.