Preoperative and postoperative assessment of nutrient intakes in patients who have undergone gastric bypass surgery.

The study of 25 morbidly obese patients who had undergone gastric bypass surgery was undertaken to determine the fat, carbohydrate (CHO), protein, and total caloric intake before and at 1, 3, 6, and 12 months postoperatively. No postoperative complications occurred, and all patients lost weight appropriately. The nutrient intakes were estimated from dietary recall. Dramatic decreases occurred in average total caloric intake from a preoperative value of 3979.4 to 351.6 kcal at 1 month, 471.3 kcal at 3 months, 932.7 kcal at 6 months, and 1091 kcal at 12 months. Fat, CHO, and protein intake decreased equally until 12 months when fat intake had reached a plateau while CHO and protein intake continued to rise. Weight reduction after gastric bypass surgery is related to decreased caloric intake, predominantly in the fat component.