According to Boston University School of Medicine (BUSM) the yo-yo pattern of overeating followed by undereating, reduces the brain’s ability to feel reward.
An estimated 15 million people compulsively eat in the U.S. It is a common feature of obesity and eating disorders, most notably, binge eating disorder. People often overeat because it is pleasurable in the short term, but then attempt to compensate by dieting, reducing calorie intake and limiting themselves to “safe,” less palatable food. However, diets often fail, causing frequent “relapse” to overeating of foods high in fat and sugar (palatable foods).
Desperate for another hit? Or going “cold turkey”?
Yo-Yo dieters’ brains eventually show “drug-addict” like reactions.
“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,”Pietro Cottone, PhD, associate professor of pharmacology & experimental therapeutics at BUSM and co-director of the Laboratory of Addictive Disorders.
In the experiment half the people were given a high sugar, chocolate-flavored diet (exciting food) for two days each week. For the remaining days of the week they were given a standard control diet (dull food). Essentially they “yo-yo’ed” between exciting food and dull food.
The other half of the people were given the standard, dull, food all the time.
Yo-yo dieters’ brains became immune to the effects of amphetamines. They needed a “bigger hit” to feel rewarded.
When these people were given amphetamines, (yes, the researchers gave them all drugs – under medical supervision of course!) the amphimines did not have as much effect on the yo-yo dieters as it did on the people who ate the standard, dull diet.
Researchers found that the yo-yo dieters’ brains behaved similar to drugs addicts’, specifically a “crash” in the reward system.
When people become used to eating highly rewarding, sweet foods, when they can no longer get those rewarding foods, they have a similar “downer” to drug addicts who are going cold turkey.
Drug addicts eventually become immune to the “reward feelings” caused by the drug, which leads to drug addicts needing a bigger and bigger “high” every time. Similarly yo-yo dieting, leads to a constant search for a “bigger high” with more rewarding food, after a period of dull, unrewarding standard food.
“Compulsive eating may derive from the reduced ability to feel reward. These findings also provide support to the theory that compulsive eating has similarities to drug addiction.”
The researchers hope these findings spark new avenues of research into compulsive eating that will lead to more effective treatments for obesity and eating disorders.