Study: Being a couch potato may be genetic
ST. PAUL, Minn. (UPI) -- U.S. scientists say that there may be a biological basis for being a couch potato because some brains are wired to encourage activities that consume calories.
University of Minnesota researchers find that the brains of rats bred to be lean are more sensitive to a chemical produced in the brain, orexin A, which stimulates appetite and spontaneous physical activity such as fidgeting and other unconscious movements.
Compared to rats bred to be obese, the lean rats had a far greater expression of orexin receptors in the hypothalamus, according to senior study researcher Catherine M. Kotz.
"The greater expression of orexin receptors suggests the lean rats' brains were more sensitive to the orexin the brain produces," said Kotz.
"Many people focus on diet, but it may be more feasible for some people to stand or move more throughout the day as a way to control their weight."
Contrary to common belief, metabolism rates don't vary greatly from person to person and weight gain usually results from eating too much, burning too few calories, or both, according to Kotz.
The findings are published in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology.
Copyright 2006 by United Press International