Science shows that genetics plays a role in becoming overweight or obese. Genes can directly cause obesity in disorders such as Bardet-Biedl Syndrome and Prader-Willi Syndrome. In some cases, a person's genetic code and behavior may both be needed for a person to be overweight. In other cases, multiple genes may increase one's susceptibility for being overweight or obesity and require outside factors; such as abundant food supply and/or little physical activity.
In some cases of genetic coding, a person is destined to have trouble with their weight. In other cases, it is the combination of genetic coding and the person's behavior or environment which contribute to the overweight, obese or morbidly obese condition.
For more information on the genetics and obesity visit Obesity and Genetics: A Public Health Perspective.