How extensive is the gastric bypass surgery?

Major surgery: Significant rerouting of the plumbing. It is a combo restrictive (make a small stomach pouch) and malabsorptive (shorten effective absoptive capacity of small bowel). "centers of excellence", with ample experience (not the occasional bypass operator) reasonably safe track record. Can have significant complications at and after surgery, short and long term. Balance risk/benefits of surg or not.

Not really. : The gastric bypass is now laparoscopic and takes about one hour. Most patients go home the next day. Back at work in 2 wks. Driving to store in one week. In experienced hands, about as safe as appendectomy. Specifically suited for patients with significant acid reflux (heartburn) or severe diabetes.