Gary Taubes gave a lecture at UW last Thursday. Thanks to all the Whole Health Source readers who showed up. Gary's talk was titled "Why We Get Fat: Adiposity 101 and the Alternative Hypothesis of Obesity". He was hosted by Dr. Philippe Hujoel, the UW epidemiologist and dentist who authored the paper "Dietary Carbohydrates and Dental-Systemic Diseases" (1).
Gary's first target was the commonly held idea that obesity is simply caused by eating too much and exercising too little, and thus the cure is to eat less and exercise more. He used numerous examples from both humans and animals to show that fat mass is biologically regulated, rather than being the passive result of voluntary behaviors such as eating and exercise. He presented evidence of cultures remaining lean despite a huge and continuous surplus of food, as long as they stayed on their traditional diet. He also described how they subsequently became obese and diabetic on industrial foods (the Pima, for example).
He then moved into what he feels is the biological cause of obesity: excessive insulin keeping fat from exiting fat cells. It's true that insulin is a storage hormone, at the cellular level. However, fat mass regulation involves a dynamic interplay between many different interlacing systems that determine both overall energy intake and expenditure, as well as local availability of nutrients at the tissue level (i.e., how much fat gets into your fat tissue vs. your muscle tissue). I think the cause of obesity is likely to be more complex than insulin signaling.
He also offered the "carbohydrate hypothesis", which is the idea that carbohydrate, or at least refined carbohydrate, is behind the obesity epidemic and perhaps other metabolic problems. This is due to its ability to elevate insulin. I agree that refined carbohydrate, particularly white flour and sugar, is probably a central part of the problem. I'm also open to the possibility that some people in industrial nations are genuinely sensitive to carbohydrate regardless of what form it's in, although that remains to be rigorously tested. I don't think carbohydrate is sufficient to cause obesity per se, due to the many lean and healthy cultures that eat high carbohydrate diets*. Gary acknowledges this, and thinks there's probably another factor that's involved in allowing carbohydrate sensitivity to develop, for example excessive sugar.
I had the opportunity to speak with Gary at length on Thursday, as well as on Friday at dinner. Gary is a very nice guy-- a straightforward New York personality who's not averse to a friendly disagreement. In case any of you are wondering, he looks good. Good body composition, nice skin, hair and teeth (apologies to Gary for the analysis). Philippe and his wife took us out to a very nice restaurant, where we had a leisurely four-hour meal, and Dr. Mike Eades was in town so he joined us as well. Mike has a strong Southern accent and is also a pleasant guy. Philippe and his wife are generous and engaging people. It was a great evening. The restaurant was nice enough that I wasn't going to be picky about the food-- I ate everything that was put in front of me and enjoyed it.
* I'm talking about prevention rather than cure here. I acknowledge that many people have had some success losing fat using low-carbohydrate diets, including two gentlemen I met on Thursday.