A recent study conducted by Yerkes Primate Research Center in Atlanta, which observed dominant and subordinate rhesus monkeys, found that stressed female monkeys ate more fat and sugar than those who weren't under stress. High-fat, high-caloric foods increase dopamine, serotonin, and endorphin levels—chemicals that cause good feelings—and researchers suspect that monkeys lower in the hierarchy cope with harassment from their superiors by binge eating. (ABC News)
What the commentators said
This may be true for monkeys, said John Tierney in the New York Times' TierneyLab blog, but "it would be simplistic to conclude that this is the grand explanation for higher rates of obesity among humans of lower socioeconomic status." Human beings "respond to stress and foods in complicated ways," with many factors that influence stress and and eating habits. So while the study shows a correlation between stress and binge-eating, it does not prove that stress causes obesity.
But there already is evidence that links status and obesity in humans, said Kate Lunau in Macleans' What the Health? blog. The Whitehall study, in the 1980s, found that low-status British civil servants are more prone to obesity and other health conditions.
Either way, said the blog Neuroanthropology, the stress-binging pattern is part of a larger, more dynamic system of external and internal forces. The "cultural mandates of beauty," the "evolution of self control," and the reinforcing cycle of stress and dopamine all "facilitate the restraint and binge dynamic." Rhesus monkeys don't have the "emotional baggage" that humans do. "We humans can internalize our mix of ideals and status, and that then plays into our overall brain function, behavior, and sense of self."