According to a study published by The American Physiological Society, a certain chemical produced in the brain and called orexin A causes restlessness and physical activity in individuals, favoring calories burning and regulating body weight.

The study is called "Elevated hypothalamic orexin signaling, sensitivity to orexin A and spontaneous physical activity in obesity resistant rats," and is published in the online edition of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. Trials have been conducted on obesity prone and obesity resistant rats. Results showed that the animals that were fed to be obese showed reduced levels of orexin A in the brain. On the contrary, lean mice presented far more orexin receptors in the hypothalamus.

Orexin A chemical compound works against weight gain by making our body more restless and fidget. Even if we sometimes may not be aware of body's movements and other unconscious behaviors that relate to restlessness, it seems that this is very beneficial against body weight and fat, as the fidgeting burns calories.

Catherine M. Kotz, the study's senior researcher, from the VA Medical Center, University of Minnesota stated: "The greater expression of orexin receptors suggests the lean rats' brains were more sensitive to the orexin the brain produces. The results point to a biological basis for being a couch potato. Many people focus on diet, but it may be more feasible for some people to stand or move more throughout the day."

Research findings also showed that orexin A injected by experts in the lateral hypothalamus area of brain caused more energy and physical activity in lean mice and no improvement in the activity of obese mice.

"We knew from previous studies that orexin stimulated physical activity, and so we wanted to find out whether it enhances activity more in lean rats than in obese rats. Not only do the lean rats have a higher base activity rate but they respond more to orexin," Dr. Kotz pointed out.

Taking into account the fact that both the obese and lean mice have been fed with the same amount of food and the same number of calories, the key factor that helps controlling body weight was proved to be "physical activity." As lean mice present higher levels of orexin A in the brain, they are prone to do more physical activities and eat less. But when scientists reduced levels of orexin A in lean mice's brain, they acted exactly like their obese counterparts, making less movements and activities.

"If we can get obese individuals to a slightly higher level of activity, that would be very beneficial," senior researcher of the study concluded.