There are two components to the procedure. First, a small stomach pouch, approximately one ounce or 30 mL in volume is created by dividing the top of the stomach from the rest of the stomach. Next, the first portion of the small intestine is divided, and the bottom end of the divided small intestine is brought up and connected to the newly created small stomach pouch. The procedure is completed by connecting the top portion of the divided small intestine to the small intestine further down so that the stomach acids and digestive enzymes from the bypassed stomach and first portion of small intestine will eventually mix with the food.
The gastric bypass works by several mechanisms. First, similar to most bariatric procedures, the newly created stomach pouch is considerably smaller and facilitates significantly smaller meals, which translates into fewer calories consumed.
- Produces significant long-term weight loss (60-80% excess weight loss)
- Restricts the amount of food that can be consumed
- May lead to conditions that increase energy expenditure
- Produces favorable changes in gut hormones that reduce appetite and enhance satiety
- Typical maintenance of >50% excess weight loss
- Is technically a more complex operation than the Adjustable Gastric Band or Laproscopic Sleeve Gastrectomy and potentially could result in greater complication rates
- Can lead to long-term vitamin/mineral deficiencies particularly deficits in vitamin B12, iron, calcium, and folate
- Generally has a longer hospital stay
- Requires adherence to dietary recommendations, life-long vitamin/mineral supplementation, and follow-up compliance