Obesity is defined as having a body mass index (BMI) of 30 or higher. BMI is a person's weight in kilograms divided by the square of their height in meters. Factors influencing obesity include genetics, environmental influences like increased calorie intake and decreased energy expenditure, diet, culture, and fetal nutrition. Obesity can lead to health issues such as type 2 diabetes, cardiovascular problems, sleep-breathing abnormalities, cerebrovascular disease, and various cancers. Management of obesity involves dieting, exercise, weight loss programs, medication, and sometimes surgery.