Weight loss after jejuno-ileal bypass surgery.

The changes in body weight after jejuno-ileal bypass surgery in 23 cases of massive obesity are reported. After an initial rapid weight reduction, body weight fell at a constant rate over six months. The weight reduction curves correspond to a zero order kinetics. After the first six months the rate of weight loss declined, but the weight continued to fall. By 12 to 24 months after the operation stabilization of body weight at an average level corresponding to 38% of the preoperative weight was attained.