Monkey Diets Offer New Clue on Binge Eating

New research found that stressed monkeys ate more fat and sugar.

May 21, 2008 — -- Many believe the worst day at work can be curbed by inhaling a big tub of ice cream, but now scientists have found new evidence suggesting that bingeing isn't our fault -- it's biology.

Researchers studying the diet choices made by monkeys say the results may explain why some humans binge after a tough day at work. They say that bingeing may not be entirely the fault of all those tantalizing food commercials that draw people to fatty foods.

Researchers at the Yerkes Primate Research Center in Atlanta found that stressed monkeys ate more fat and sugar than those who weren't under stress.

There are two classes of monkeys: the dominant ones and the subordinate ones. By studying these two varieties, researchers have learned why some humans are more likely to binge eat than others.

Surprisingly, dominant monkeys normally ate slightly more of the low-fat, high-fiber food than subordinate monkeys. Apparently, the constant bowing to their superiors curbed the subordinates' appetite.

But things changed when researchers replaced the healthy food the monkeys normally eat with fatty, sugary banana pellets. While the dominant monkeys dabbled in the new food, the subordinates started bingeing on the tasty cuisine after dark.

"We found the subordinate animals were indeed going out at night and feeding," said neuroscientist Mark Wilson, a researcher at the center.

Researchers believe the monkeys that are harassed all day long by high-ranking monkeys may just be contemplating the days' events and coping.

"Eating high-fat, high-caloric foods … they increase … dopamine levels, they increase serotonin and endorphins, all chemicals that make us feel good," said psychiatrist Julie Holland.

Even so, research shows that while monkeys felt better after their late-night binges, humans tended to feel guilt. But maybe the 72 million Americans on a diet will feel better knowing that binge eating has something to do with biology.