Obesity's Hazards And Mysteries

In Cottone's study, which appeared in PNAS in late November, one group of rats was fed "palatable", or high-sugar, chow for two days and then deprived of it for five days. Eventually, the withdrawal of the high-sugar chow triggered the release of a molecule known as corticotropin-releasing factor, or CRF, which causes anxious and depressive feelings and has been linked to relapses in drug addicts.

When exposed again to the palatable chow, the stressed mice overate compulsively in what Cottone characterized as "self-medication." After seven weeks, Cottone and his fellow researchers blocked the rats' CRF receptors. Only then were the rats able to restrain their anxious behavior and binging.

The scenario is no surprise to those who struggle with dieting. Cottone's goal is to prove that palatable foods are indeed biologically "addictive" and that dieters who flame-out are struggling with more than just a failure of willpower. (The threats of increased heart disease, cancer and arthritis risk sometimes aren’t enough on their own.) The only solution to the withdrawal and relapse cycle, he says, might be to avoid "palatable" foods in the first place.