Obesity is excess body weight, defined as a body mass index (BMI) of ≥ 30 kg/m2. Complications include cardiovascular disorders (particularly in people with excess abdominal fat), diabetes mellitus, certain cancers, cholelithiasis, fatty liver, cirrhosis, osteoarthritis, reproductive disorders in men and women, psychologic disorders, and, for people with BMI ≥ 35, premature death. Diagnosis is based on BMI. Treatment includes lifestyle modification (eg, in diet, physical activity, and behavior) and, for certain patients, drugs or bariatric (weight-loss) surgery.