obesity contributes to and aggravates many of the major diseases of affluent, west- ern cieties. Most cases of diabetes are related to obesity as are many cases of gallstones. Hypertension and hyperlipidaemia are commoner in the obese, which helps to explain why these people are excessively prone to ischaemic heart disease and cerebrovascular disease. These diseases are the main reason for the shorter life expectancy of the obese. A man who reaches his 50th birthday carrying 25lb(11.3 kg) of excess fat has 25 percent less life ahead of him than if he were slim. The obese are also more prone to develop cancer, especially cancer of the breast, uterus and colon. Surgical operations are more difficult and hazardous, with increased risk of venous thromboembolism and respiratory infections. The locomotor system also suffers, with increased osteoarthritis, especially of hips and knees, and gout. The obese move slowly and clumsily and are accident-prone. Gross or morbid obesity hinders respiratory movements and can lead to ventilatory insufficiency. Finally, there are psychological problems. Fat people cannot dress smartly or fashionably. They are often depressed by their deformity and are afraid to go out.