Obesity is a medical condition defined by excessive body fat, resulting in health problems and reduced life expectancy.
Obesity is often diagnosed using the Body mass Index (BMI), a measurement obtained by dividing a person's weight by the square of the person's height. People are considered obese when their BMI reaches 30kg/m².
Common causes include genetic predisposition, excessive food intake and a lack of physical activity. The excess calories are stored as fat, or adipose tissue. Occasionally obesity may also be the result of an endocrine disorder. The environment appears to play a major role. Sleep, stress, viruses and exposure to pollutants are also risk-increasing factors.
Obesity can lead to a number of health conditions including cancer, cardiovascular diseases, type 2 diabetes, osteoarthritis, obstructive sleep apnea and depression.
The main treatment for obesity consists of dieting and physical exercise. Medication can also be used to decrease appetite or fat absorption. In cases where diet, exercise and medication have no effect, bariatric surgery can be performed to reduce the size of the stomach with a gastric band.