While I am preparing the First Law of Thermodynamics and Obesity post I thought I’d mention:

A commenter asked why I don’t  discuss Gary Taubes’s book Good Calories, Bad Calories more as it addresses many of the issues I bring up.

My failure to cite Taubes is probably a mistake. Taubes’s lectures on the subject of obesity were instrumental in my intellectual journey. He was the first to shake me from my dogmatic slumber of calories-in vs. calories-out.

Where I break with Taubes is over the solution. Taubes seems fairly convinced on the carbohydrate-insulin hypothesis. I am more skeptical. For me carbohydrate-insulin is one of the leading candidates for a Theory of Obesity but there are a lot of questions it fails to answer.

Not least of my objections is that carbohydrate restriction is not universally and completely successful. It is more successful than calorie or fat restriction but it doesn’t have the track record of say bariatric surgery. A complete Theory of Obesity needs to explain that.

Moreover, we are rapidly learning more about the hormone regulation mechanisms involved in obesity. Leptin was discovered in 1994. The fat regulation effects of grehlin and peptide YY were discovered in 1999 and 2006 respectively.  All three seem to have an importance on par with insulin.

Its important that we don’t hang our hats on a single hormone or regulation chain. We are not even close to uncovering all of the hormones involved. The best we can say right now is that while obesity seems strongly related to hyperinsulinemia we still cannot say for sure what the cause of the obesity epidemic is.