How soon will I start to lose weight?

You will start losing weight immediately after surgery, but you may not notice any loss until the second week. With the Lap-band, weight loss is gradual and constant, approximately 1-2 pounds per week. Weight loss after gastric bypass or biliopancreatic diversion is initially rapid, slowing about nine months after surgery. At the three-week follow-up visit, we typically see a 15-to-20-pound weight loss, depending on your starting weight (i.e., heavier patients will lose more weight).