Gastric bypass (Roux-en-Y gastric bypass) is a proven procedure in the field of bariatric surgery. It is a combination of restrictive and malabsorptive techniques, which not only restricts food intake but also reduces food absorption. A small part of the stomach is formed into a small pouch, while the rest of the stomach and part of the small intestine are bypassed.

The procedure is usually performed laparoscopically and under general anaesthesia, which is known as "minimally invasive" or "keyhole surgery". The exact number of incisions may vary depending on the surgeon, but due to their small size, there are usually no aesthetic problems. During the procedure, measures are taken to prevent bleeding and leakage, followed by a series of tests to ensure the safety of the treatment.

By bypassing part of the small intestine, gastric bypass reduces the amount of nutrients absorbed. This, in combination with the smaller stomach size, leads to a faster feeling of fullness and significant weight loss. The gastric bypass procedure has proven to be highly effective and is recommended for patients with a BMI over 32 who may also have other weight-related health problems.