A number of studies suggest that patients regain weight due to the gradual enlargement of the surgically altered small stomach pouch and stoma, the connection between the stomach and small intestine. When the Roux-en-Y procedure is performed, the stomach and stoma are made very small, which slows the passage of food and creates a feeling of fullness after just a small volume of food is eaten. It is believed that when the stomach pouch and stoma gradually enlarge, the feeling of fullness is no longer present, patients can eat larger meals, and weight gain occurs.