The findings also implicate the brain's opioid, or reward, system in regulating overeating, especially when the food is extra-tempting and not only in under-fed animals. This knowledge may help even non-stressed people to avoid overeating, keep their weight down and improve their health. Behavioral Neuroscience is published by the American Psychological Association (APA).
A study by M. Flavia Barbano, PhD, and Martine Cador, PhD, at the University of Bordeaux 2 in France, separated the distinct roles in consumption played by food deprivation and the "yum" factor, establishing that the interplay between internal and external factors regulates food intake, at least in mammals. Although much has been learned about human overeating, it is easier to untangle and verify the different variables involved in controlled animal studies.
Working with laboratory rats, the researchers tested three aspects of eating behavior: motivation (how bad did they want it), anticipation (how excited were they in advance), and intake (how much did they eat), all relative to homeostasis (satiety or deprivation) and food type (ordinary lab chow or "highly palatable" chocolate breakfast cereal, as verified by a pre-test of different foods).
For motivation, the researchers measured how fast 16 rats who either had eaten freely or been put on a diet -- ran down an alley to a bowl of either chow or Choc and Crisp, a German-brand cereal. The animals ran faster when they were either food-deprived or presented with the chocolate cereal. However, when the food-sated animals were presented
Contact: Pam Willenz
American Psychological Association