“We already know that extreme diets are susceptible to fail,” explains psychological scientists Mark E. Bouton of the University of Vermont, one of the study authors. “One reason might be that the inhibition of eating learned while dieters are hungry doesn’t transfer well to a non-hungry state. If so, dieters might ‘relapse’ to eating, or perhaps overeating, when they feel full again.”
In the study, published in Psychological Science, Bouten conducted a behavioral conditioning study for 12 days on 32 female rats. After feeding, Bouten put the rats in a box with a lever that dispensed food. The rats grazed, but didn’t overeat. Over the following four days, the rats were placed in the box while they were hungry, but disabled the lever. The hungry rats were denied food in the way dieters deny themselves food.
A few days later, Bouten fed the rats and put them in the box with a fully-functioning, treat-dispensing lever. This time the full rats pressed the lever—and ate—much more than they did the first time around.
Though we can’t know for sure how humans would have reacted to this treatment, previous research suggests a similar result—here’s how faulty hunger patterns could be making you fat.
Bouten explains that when the rats couldn’t eat while hungry, they overcompensated the next time they got a shot at the treat-dispensing lever. “A wide variety of stimuli can come to guide and promote specific behaviors through learning,” Bouten and his co-authors wrote. “For example, the sights, sounds, and the smell of your favorite restaurant might signal the availability of your favorite food, causing your mouth to water and ultimately guiding you to eat. However, internal stimuli such as hunger or satiety may also promote behavior in ways that are not so adaptive.”
Perhaps the best solution is to make sure you don’t go hungry when trying to shed pounds. Keep a stash of healthy snacks you can munch sans guilt, and make sure they contain some protein and fat—think nuts or lean meat—to trigger feelings of fullness.