Dietary intake before and after gastric bypass and gastroplasty for morbid obesity in women.

Fifty-one morbidly obese women were randomized to surgical treatment with gastric bypass (GBY) or gastroplasty (GPL). Their dietary intake was assessed preoperatively and 12 months postoperatively by two methods: diet history and 4-day weighted intake. Their protein intake was also checked against urinary nitrogen losses. There was a good correspondence between the results of the two dietary methods and also between estimated protein intake and urinary loss. This makes the results reliable. After 1 year the GBY patients demonstrated a mean weight loss of 41.6 +/- 10.8 kg (P less than 0.001 versus GPL) and a mean energy intake preoperatively of about 2400 kcal/day and postoperatively of 1050 kcal/day (P less than 0.05 versus GPL). The GPL patients lost 28.9 +/- 9.6 kg as a mean and had a preoperative intake of about 2500 kcal/day and a postoperative intake of about 1300 kcal/day. There were only minor changes in the quality of the food from the preoperative to the postoperative situation. Postoperatively the daily intake of several nutrients was below minimum values of recommended or required intake.