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.
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.
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.