“What percentage of gastric bypass patients regain weight?”

It varies. The main reason why bariatric patients gain weight again is lack of compliance. (98% of cases). Patients with bariatric surgery must understand that they need to radically change their eating habits and lifestyle. If they don't stick estrictly to the diet and recommendations of their doctors their surgery is going to be useless. You must keep a low calorie diet which implies staying away from most of the things that you enjoy eating.

Some studies show 50% of those who have had gastric bypass will begin regaining weight after 2 years. It is important to work closely with a bariatric physician near you to help keep the weight off.

Most >50% will regain weight but not back to their pre-surgery weight.