Sixty-six percent of adults and seventy percent of children in the U.S. are overweight. Eating too much and not exercising are the main causes, but discoveries in the lab show that there is an explanation for the fact that some people never succeed to get or to keep fit.

Specialists have long debated whether obesity can be considered a disease or not. They also tried to figure out if lifestyle was the only factor that influence one’s health or if the weight simply depended on hereditary aspects.

Recent studies have proven that several genes, such as the FTO gene, seem to influence obesity.

"If you do have the FTO gene, it does put you at risk for becoming obese and having type 2 diabetes and extra body fat," stated Emily Rubin, RD, weight loss dietitian.

Researchers from the University of Florida also conducted numerous investigations, which pointed out the existence of eleven genetic mutations that caused a receptor to malfunction. That receptor suppresses hormone leptin, controlling the appetite. Another relevant factor in getting overweight is the level of impaired dopamine, which determines overeating.

Metabolism reacts at different types of incentives. An interesting discovery was made by researchers at the University of Chicago Medical Center, who noticed a rare mutation in a woman and her 10-year-old son. Their metabolisms extracted the necessary energy from very little quantities of food, so they had to eat very little in order to maintain their weight.

It might appear discouraging to know obesity is favoured by genetic factors. However this discovery does not mean that exercise and diet don't keep their status of effective weapons in the fight with overweight.