Boston University School of Medicine (BUSM) researchers have found that the recurring cycle that occurs in yo-yo dieting (a pattern where a person overeats followed by a time where their caloric intake is severely restricted) diminishes the brain’s ability to perceive a reward. It may also lead to compulsive eating for some people.
Compulsive eating is relatively common in the United States, affecting approximately 15 million people. Overeating occurs because it feels good at the time, but then people try to compensate for it by going on diets where they limit their daily calories or declare only certain foods “acceptable” to eat. This weight-loss method often fails because it’s too restrictive. The person rebels against the diet by overeating foods with high sugar and fat content.
Compulsive Eating Cycle “Similar to Taking Drugs”
Corresponding author Pietro Cottone, Ph.D., an associate professor of pharmacology & experimental therapeutics at BUSM, explained that researchers are just beginning to understand the “addictive-like properties” of food and how repeating this cycle of eating high levels of sugar is “similar to taking drugs.” It may affect the way the brain functions, leading to compulsive behaviors.
The BUSM researchers performed experiments on two groups of participants.
• The first group ate a standard control diet five days each week. For two days per week, this group ate chocolate-flavored food that had a high level of sugar.
• The second group ate the control diet for the entire seven days per week.
The first group (the one that was given two kinds of foods) started to binge on sweets and refused to eat “regular food.” Both groups of participants were injected with an amphetamine. This type of drug releases dopamine (the brain’s “feel-good” neurotransmitter) and produces a reward.
Behavioral Tests Performed After Drugs Administered
While under its influence, the participants were asked to perform several behavioral tests.
• The control group became hyperactive after being given the amphetamine, which was expected. The group who received a varied diet did not.
• When a test on the conditioning properties of amphetamines was conducted, the control group “was attracted to environments” where they had received amphetamines previously and the varied group was not.
• Researchers measured how well the amphetamine stimulated the brain reward circuit of both groups. The control group responded to the drug; however, the varied group did not.
Lead author Catherine (Cassie) Moore, Ph.D, who had previously trained in BUSM’s Laboratory of Addictive Disorders commented that the varied group displayed “similar behavioral and neurobiological changes observed in drug addiction: specifically, a ‘crash’ in the brain reward system.” Dr. Moore went on to say that compulsive eating may result from a person developing a lower capacity to experience a reward. She stated that the study’s results tie into the theory that compulsive eating has some traits in common with addiction.