A pattern of overeating followed by undereating may reduce the ability of the brain to feel reward and drive compulsive eating, a common feature of eating disorders, suggests a study published online in the journal Neuropsychopharmacology.
“We are just now beginning to understand the addictive-like properties of food and how repeated overconsumption of high sugar—similar to taking drugs—may affect our brains and cause compulsive behaviors,” said corresponding study author Pietro Cottone, PhD, of the Boston University School of Medicine in Massachusetts.
The findings stem from a study involving rats which were divided into 2 groups. One group (the cycled group) was fed a high-sugar diet 2 days of the week and a standard control diet the remaining days. The other group (the control group) was fed the control diet all week long.
The cycled group, researchers reported, quickly developed compulsive, binge-eating behavior when provided the sweet food but refused to eat the control food.
After both groups were injected with amphetamine, a psychostimulant that releases dopamine and produces reward, researchers noted several differences:
• The control group demonstrated hyperactivity as expected, but the cycled group did not.
• The control group was attracted to environments where they previously received amphetamine, but the cycled group was not.
• The cycled group had deficits in their mesolimbic dopamine system, the part of the brain responsible for feeling reward or pleasure, that resulted in less dopamine overall, the release of less dopamine in response to amphetamine, and dysfunctional dopamine transporters compared with the control group.
“Our data suggest that a chronic cyclic pattern of overeating will reduce the brain's ability to feel reward—feeling satiated,” said lead author Catherine Moore, PhD, a former graduate student at the Boston University School of Medicine. “This results in a vicious circle, where diminished reward sensitivity may in turn be driving further compulsive eating.”
The findings suggest future research into compulsive eating treatment could focus on rebalancing the mesolimbic dopamine system, researchers noted.
Moore CF, Leonard MZ, Micovic NM, Miczek KA, Sabino V, Cottone P. Reward sensitivity deficits in a rat model of compulsive eating behavior. Neuropsychopharmacology. 2019 October 17;[Epub ahead of print].