A surprisingly high prevalence of obesity is reported in the population of Bombay, India. However, the response of the Indian population to a nutritionally adequate hypocaloric diet for the treatment of obesity is unknown and, therefore, this study was undertaken to investigate the response to an out-patient diet therapy in India and to compare and contrast with similar reports from western societies, with special reference to dietary habits, waist-to-hip ratio (WHR), and smoking habits. The effect of a balanced hypocaloric diet (1100–1900cal) for 15 weeks was studied in 1117 patients, and their response to the treatment was analysed. During the study period, the body weight of the patients decreased by 10–13%, and a corresponding decrease in body mass index, body fat content, and blood pressure was also observed. The drop-out rate was 56.6% for males and 51.5% for females. Vegetarians and non-vegetarians had similar percentage obesity, and the rate of reduction did not depend on the diet type. The WHR for non-vegetarian females was higher than that for vegetarians. The amount of reduction in percentage obesity was not influenced by the WHR. Smokers had higher percentage obesity and also lost a greater amount of weight compared to non-smokers. The results in terms of the weight lost, and the drop-out rate, are comparable with similar reports from developed countries. The response obtained, and the trends observed with respect to the diet type, WHR and smoking, differ from the prevalent view, and may indicate trends peculiar to the Indian population.