Obesity is increasing in most developed countries. The BMI (height of the patient in metres, divided by weight in kilograms) indicates the degree of obesity. The ideal BMI is 20 to 25. From 30 to 34.9 is obese (grade I), 35 to 39.9 is obese (grade II) and >40 is morbidly obese (grade III). The waist to hip ratio, upper limit for men is 0.9 and women is 0.85, is a better predictor for cardiovascular risks. Many factors lead to obesity: genetics, family history, lifestyle, eating habits, socioeconomic factors, psychiatric problems, medications and hormonal diseases can aggravate the problem. Obesity increases the risks of diabetes, coronary heart disease and osteoarthritis. Early dietary advice for the young can be helpful in minimising future problems. Blood pressure must be checked, and urine analysed for glucose and protein, fasting blood glucose and lipids. Most important is dietary advice and adequate exercise. Orlistat is available over the counter and can be effective but is not without side effects so needs careful monitoring. Gastric surgery may be effective but should be reserved for severe cases.