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When Does Dieting Get Hard? When We're Not Hungry, Says New UVM Study

Implications for Weight Loss Programs, Addiction Treatment

Plate of Unfinished Food
A new study by University of Vermont researchers suggests that control of consumption isn't simply a great act of will power but possibly is guided by the states of hunger and satiety. (Photo: Brian Jenkins)

When we’re on a diet, we’ll avoid cheeseburgers and ice cream and other foods we love, even though we’re ravenous and hankering for them. Once off the diet, we’ll often return to stuffing ourselves with goodies – even if we aren’t hungry.

We learn self-control while we’re dieting. But a new study by University of Vermont researchers suggests that control of consumption isn’t simply a great act of will power but possibly is guided by the states of hunger and satiety.

During a diet, hunger may become the context in which we learn to deny eating impulses. When we stop dieting and no longer feel hungry, the context vanishes, and we may lose the inclination to restrain our food intake. That’s perhaps a reason why weight regain after a diet ends is so common.

Context matters, explains Mark Bouton, the UVM psychology professor who co-authored the study with his Ph.D student Scott Schepers, scheduled for publication in the journal Psychological Science. For years, he has looked at the importance of context in controlling behavioral and emotional responses.

His research shows that the suppression of behavior or emotion depends upon context – a physical setting, a time period or an internal state such as hunger, mood or the influence of a drug. And the behavior or emotion will “renew” when the context changes or returns to where it was when the response was learned.

For the study, Schepers and Bouton tested rats in two different “contexts” – hungry or satiated. The satiated rats, fed a plentiful amount, could press a little lever to dispense a sweet-fatty pellet, like candy. Even though they weren’t hungry, they chose to press for the treat.

Then, when they were food-deprived for 23 hours a day, the rats didn’t get any pellets when they pressed the lever. Before long, they stopped pressing. They learned to inhibit their food-seeking behavior – but only while they were hungry. When they were satiated again by eating a normal amount of food, they started pressing the lever to get pellets again.

“If you learn to inhibit your behavior when you’re hungry and then are tested in a non-hungry, satiated state, the behavior comes back,” Bouton said. “The real point is hunger and satiety are internal contexts that can control behavior and behavioral inhibition.”

Bouton is collaborating with University of California San Diego researchers who work with obese children. The study teaches the kids to inhibit their craving in the presence of food and food cues, and also studies the role of context.

“You need to practice the inhibition in the context where it’s going to matter,” Bouton says. “You want to learn to control your eating in the presence of all those cues that have been so hard.”

Bouton’s research also could inform treatment of opioid or other drug abuse. He draws parallels between overeating and addiction, alcoholism and smoking – habit-forming behaviors in response to cues, and influenced by context. Drug rehabilitation programs, like diets, create a context for suppressing the behavior, Bouton says, so it’s not surprising that addicts can relapse when they get out of such programs and back to their normal lives.

Bouton, assistant director of UVM’s Neuroscience Graduate Program, specializes in understanding basic learning processes– the development of emotional or behavioral responses in association with certain events or cues. Years ago, he started looking at fear conditioning to understand phobias, anxiety and post-traumatic stress disorder. When rats received an electric shock every time they heard a particular sound, they learned to grow fearful upon hearing that sound. Then, when the sound played over and over without the shock, the fear response subsided, or became “extinguished.”

The clinical psychology practice of exposure therapy works on this concept: By exposing patients again and again to the trigger that makes them scared or anxious, without any harm coming to them, their response gradually subsides. But if the context changes or returns to a previous state, the response can resurface. It’s not erased.

“You can learn things, but as the world changes, we need to be able to change our behavior or change our knowledge,” he said. “We can get rid of the fear, but it comes back really easily.”

Because context is key to controlling behavior, Bouton hopes his work expands the understanding of this concept and sheds light on what causes – and could inhibit – addictive behavior.