Stephan Guyenet on the Obesity Epidemic

One of the longest reads I think I've ever seen on Boing Boing, but worth it: Nutrition researcher and neurobiologist Stephan J. Guyenet explains the current thinking on causes of the U.S. obesity epidemic.

Commercial foods are professionally designed to maximize reward, because reward is precisely what keeps you coming back for more. Processed junk foods such as ice cream, fast food, sweetened soda, cookies, cake, candy, pizza and deep fried foods are all archetypal hyper-rewarding foods.  Palatability is a related concept—it’s determined in part by inborn preferences (e.g., a taste for sugar and energy dense foods), and in part by the reward system (acquired tastes).

Palatability is governed by the hedonic system in the brain, which is closely integrated with the reward system. Imagine yourself sitting at the dinner table, stuffed after a large meal. Then the cake and ice cream appear, and suddenly you have enough room left for another 250 calories of food. Would you have eaten a large, unseasoned baked potato (250 calories) if someone had put one in front of you at that point? Foods that stimulate the hedonic system have a well known ability to increase food intake, and this effect can be replicated using drugs that activate these circuits directly 

Overlaying two of Guyenet's graphs reinforces his line of thinking:



I've taken Guenet's graph of obese and very obese people as a percent of the U.S. population, post-1960, and laid it atop the graph showing percent of food spending at and away from home, with the rise of fast food since the late 1960s highlighted in red.

His full article makes it clear that this is not the only reason people become obese -- he mentions mid-19th century autopsies of obese people who showed damage in their hypothalamuses, for instance. But it could account for what changed so suddenly in the last 50 years.

Read the whole thing for yourself. The comments are even worth reading, for the most part, with Guyenet responding. Almost like a real conversation on an important issue.

Guyenet's blog is Whole Health Source: Ancestral Nutrition and Health