Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have a negative effect on health. It is most commonly caused by a combination of excessive food intake, lack of physical activity, and genetic susceptibility. It is mostly preventable through a combination of social changes and personal choices. Changes to diet and exercising are the main treatments. It is a leading preventable cause of death worldwide, with increasing rates in adults and children. In 2015, 600 million adults (12%) and 100 million children were obese. Obesity is more common in women than men.