Causes of obesity

Till the latest, obesity was held to be the cause of sedentary lifestyle and continuous calorie intake in excess. Although these factors indisputably contribute to obesity, proof exist that genetically factors also greatly influence its appearance.

According to a study made on 540 people, there is a solid link on child and parents BMI index. For approximately 70% on the studied persons obesity was explained trough genetics. A more recent study made by David B. Allison, PhD, director of the University of Alabama at Birmingham clinical nutrition research center and his colleagues showed another 10 other possible causes of obesity, among which sleep debt, as getting too little sleep can increase body weight.

Other causes included pollution, air conditioning, decreased smoking, different drugs including contraceptives, steroid hormones, diabetes drugs, some antidepressants and blood pressure drugs.

As seemingly middle-aged people and Hispanic-Americans tend to be more obese than young European-Americans, ethnicity was also included on Dr. David’s list. They’ve also found evidence that the older a woman is when she gives birth, the higher her child's risk of obesity.

At the last three positions on the list takes place the ancestors' environment, obesity linked to fertility and the unions of obese spouses, as obese women tend to marry obese men.
The different the causes may be, the most common cause is multiple, linked strongly to environmental and behavioral factors.