The frequency of obesity occurrence is constantly increasing all over the world and becoming global epidemic. Facing the lack of the efficiency of conservative treatment, patients with II and III degree of obesity are qualified for surgical treatment; however, the efficiency of surgical treatment is connected with permanent change of nutritional habits and previous lifestyle of the patient. Modification of the way of nutrition, regardless of the type of bariatric procedure, should especially include the lowering of food energetic value and change of type, consistency and size of consumed food. Nutritional treatment after bariatric procedures is multistage. It includes clear liquid diet, full liquid diet, pureed diet, mechanically altered soft diet and regular diet. Gradual expanding of... the diet protects gastrointestinal tract from chemical, mechanical and thermal irritation by the food. It also should prevent nutritional deficiencies. Significant influence on the result of surgical treatment of obesity has also regular intake of food, consuming products with high nutritional value, avoiding confectionery and fat products, consuming proper amounts of protein (60-80 g/day) and vitamin-mineral supplementation.