A new study suggests fidgeting may be a factor in deciding whether a person is overweight or thin.
Researchers found that lean rats are sensitive to a brain signal which causes restlessness. Fat rats do not have this sensitivity.
Catherine M. Kotz, of the University of Minnesota and the Minnesota Obesity Center, says, "The results point to a biological basis for being a couch potato."
Kotz and colleagues bred lean rats with other lean rats until they got obesity-resistant rats.
They also bred overweight rats with fat rats until they got a strain of obesity-prone rats.
Motion detectors showed the obesity-resistant rats were much more active than obesity-prone rats.
The findings suggest being active is a key factor in weight loss.
The researchers also found the brains of the lean rats were sensitive to a chemical called orexin. When it was injected into the rats’ brains, they became more restless.
However orexin did not have a noticeable effect on the overweight rats.
The study appears the "American Journal of Physiology-Regulatory, Integrative and Comparative Physiology."
