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In research that sheds light on the perils of yo-yo dieting and repeated bouts of sugar-bingeing, researchers from The Scripps Research Institute have shown in animal models that cycling between periods of eating sweet and regular-tasting food can activate the brain's stress system and generate overeating, anxiety, and withdrawal-like symptoms.
"When many people diet, they try to avoid fattening foods that taste good, but ultimately end up going back to their regular eating habits," said senior author Eric Zorrilla, Ph.D., an associate professor and member of the Pearson Center for Alcoholism and Addiction Research and Harold L. Dorris Neurological Research Institute at Scripps Research. "We found that rats cycled in this way between palatable food and less tasty, but otherwise acceptable, food, begin to binge on the sweet food, stop eating their regular food, and show withdrawal-like behaviors often associated with drug addiction. As in addiction to drugs or ethanol, the brain's stress system is involved in each of these changes."
"Our research suggests that this eating pattern leads to a vicious circle," explained Pietro Cottone, Ph.D., who is co-first author of the paper with Valentina Sabino, Ph.D.; both are former postdoctoral fellows at Scripps Research who are now assistant professors and co-directors of the Laboratory of Addictive Disorders at Boston University School of Medicine. "The more you cycle this way, the more likely it is you cycle again. Having a 'free day' in your diet schedule is a risky habit."
The research is being published in an advance, online Early Edition of the journal
Proceedings of the National Academy of Sciences (PNAS) the week of November 9, 2009.