The prevalence of obesity is increasing rapidly, and it is a major health problem, especially in Western countries. Bariatric surgery causes significant and permanent weight loss and improves the quality of life. It ameliorates or eliminates most of the obesity-related comorbidities. Isolated gastric restriction procedures are technically easy to perform, the morbidity and mortality are low, but the weight loss is unsatisfactory in patients who ingest high-energy food. Combined gastric restriction with gastric bypass or intestinal malabsorption procedures cause greater weight loss, but more nutritional complications.