Though it's the most commonly used, gastric bypass is just one kind of weight-loss surgery. Other types include:

LAP-BAND adjustable gastric banding (LAGB). The surgeon uses an inflatable band to partition the stomach into two parts by wrapping the band around the upper part of your stomach. Pulling it tight like a belt, the surgeon creates a tiny channel between the two pouches. The band keeps the opening from expanding and is designed to stay in place indefinitely. It can be adjusted or surgically removed if necessary. LAGB is gaining popularity because it's a simpler procedure and has a lower complication rate when compared with more-involved procedures. However, LAGB causes less weight loss and a slower rate of weight loss than does the Roux-en-Y gastric bypass. This surgery isn't recommended for people who have certain medical conditions, such as Crohn's disease, large hiatal hernias or a history of gastric ulcers.
Vertical banded gastroplasty. This operation, also referred to as stomach stapling, divides the stomach into two parts — limiting space for food and forcing you to eat less. There is no bypass. Using a surgical stapler, the surgeon divides your stomach into upper and lower sections. The upper pouch is small and empties into the lower pouch — the rest of your stomach. Partly because it doesn't lead to adequate long-term weight loss, this weight-loss surgery has fallen out of favor.
Biliopancreatic diversion with duodenal switch. In this procedure, the surgeon removes about 80 percent of the stomach. The valve that releases food to the small intestine is left along with a limited portion of the small intestine that normally connects to the stomach (duodenum). The surgery bypasses the majority of the intestine by connecting the end portion of the intestine to the duodenum near the stomach. This weight-loss surgery offers sustained weight loss, but it presents a greater risk of malnutrition and vitamin deficiencies and requires close monitoring. It's generally used for people who have a body mass index greater than 50.