Eating behavior patterns were studied in 80 gastric bypass patients at 6, 12, and 24 months postoperatively. Significant reduction occurred in the amount of food eaten and in the frequency of eating. An unexpected result was the selective reduction of food eaten in certain food categories. The reduction of calorically-dense high carbohydrate foods indicates that gastric bypass surgery may have an effect on the digestion and absorption of food as well as the mechanical impairment of food intake secondary to the small stomach pouch.