Lady Rats Can Probably Blame Their Binge Eating on Their Lady Rat Parts

A study (scientific and rat-infested by its very nature) published recently in the International Journal of Eating Disorders is the first ever to establish sex differences in rates of binge eating in animals. Well, not animals, really, so much as the scuttling disease portmanteaus we affectionately call “rats,” but the results of this study could have implications for human binge eaters.

Binge eating is at the center of many eating disorders, including bulimia nervosa and anorexia nervosa (it has nothing, however, to do with gypsy curses that make you…thinner). Women and girls are four to 10 times more likely than males to suffer from an eating disorder, a statistic that many scientists believe is linked to the shoulder-buckling societal pressures women face to look like female comic book heroines. Only thinner and with flawless skin and magic hair that always seems to be shimmering in a ray of mid-June sunlight.

According to Kelly Klump, professor of psychology at Michigan State University and auspiciously-named lead author of this study, most theories for the root causes of binge eating focus almost exclusively on cultural or psychological factors. “But this study suggests that biological factors likely contribute as well,” Klump wrote, “since female rats do not experience the psychosocial pressures that humans do, such as pressures to be thin.”

Futurity summarized the study and its findings thusly:

Klump and colleagues ran a feeding experiment with 30 female and 30 male rats over a two-week period, replacing the rodents’ food pellets periodically with vanilla frosting. They found that the rate of binge eating “proneness” (i.e., the tendency to consume the highest amount of frosting across all feeding tests) was up to six times higher in female as compared to male rats.

The tendency to binge eat may be related to the brain’s natural reward system, or the extent to which someone likes and seeks reward, Klump says. The researchers currently are testing the rats to see if female brains are more sensitive and/or responsive to rewarding stimuli (e.g., high-fat, high-sugar food) and the chemicals that trigger reward behavior.

The real takeaway here is that the differences between male and female tendencies to binge may have more to do with sex than scientists initially supposed. However, the difference in rates of binge eating between human men and women might not be nearly as dramatic as many people think, since society urges men to eat like starving lumberjacks and to therefore not dwell on the fact that they may actually be binge eating rather than pacifying their inner Paul Bunyan.