The ladies who lunch do not obsess about their weight in the rhesus monkey compound at the Yerkes National Primate Research Center in Atlanta. Food is freely available, and the high-status females do not pride themselves on passing it up. They don’t seem to stigmatize obesity  there is no equivalent of a Kirstie Alley joke  and they certainly don’t turn themselves into Social X-Rays.

In fact, the dominant females ordinarily eat a little more than the subordinates. The lower status monkeys can get as much food as they want but seem to have less of a desire to eat, perhaps because of the higher level of stress hormones in their brain. The anxiety of constantly toadying to their social superiors seems to curb their appetite, researchers suspect, at least when their regular high-fiber, low-fat chow is on the menu.

But suppose you tempted them with the equivalent of chocolate and potato chips and ice cream? Mark Wilson, a neuroscientist at Emory University, and a team tried that experiment at Yerkes by installing feeders with a constant supply of banana-flavored pellets  not exactly Dove bars, but they had enough sugar and fat to appeal even to human palates. (In the interest of science, I sampled a few pellets.)

Once these foods were available, the low-status monkeys promptly developed an appetite. They began eating significantly more calories than their social superiors. While the dominant monkeys dabbled in the sweet, fatty pellets just during the daytime, the subordinate monkeys kept scarfing them down after dark.