The Roux-en-y Gastric bypass is performed by creating a small gastric pouch (approximately 30cc) that induces significant restriction. This pouch (which is separated from the rest of your stomach) is then connected to your intestines in a way that bypasses up to 6 feet of bowel. The mechanism of weight loss after the Roux-en-Y Gastric Bypass is complex and is still being studied, but is believed to be a result of the restriction, the malabsorption, and an alteration in certain hormones related to appetite and metabolism.

The Roux-en-Y Gastric Bypass operation can be performed either using the laparoscopic technique or by using the open technique. Advantages to the laparoscopic technique may include a faster recovery, lower risk of hernia, lower risk of wound infection, improved cosmesis, and less pulmonary complications.

The Roux-en-Y Gastric Bypass provides durable weight loss that can approach 60-80% of your excess weight. Weight loss peaks between 18 and 24 months and then there is a slight weight regain before you stabilize at your new weight. In most patients, the weight loss is superior to that of the Lap Band. There is a low incidence of protein malnutrition, and there is a marked improvement (and in some cases complete resolution) of certain obesity-related comorbidities. Conditions that are known to improve dramatically include diabetes, sleep apnea, osteoarthritis, high blood pressure, reflux disease, and high cholesterol.

Complications after the Roux-en-Y Gastric Bypass are divided into those that happen early and those that happen later. Early complications can include (but are not limited to) anastomotic leak, wound infection, blood clot in the leg, pulmonary embolism, bleeding at the staple line, respiratory failure or pneumonia, and bowel obstruction. Late complications can include incisional hernia, bowel obstruction, internal hernia, stoma stenosis, marginal ulcers, and nutrient deficiencies. Mineral supplements are needed for the rest of your life and include Iron, Calcium, Vitamin B12, and a Multivitamin.

Some patients experience the "dumping syndrome" which can occur after eating certain types of sweet foods. If you experience lightheadedness, skin flushing, heart palpitations, diarrhea, or nausea and crampy belly pain shortly after eating, you may be experiencing "dumping"and should contact your doctor. The gastric bypass is considered a permanent operation, although in certain situations it can be reversed with a second major operation that carries additional risks (see revisional surgery).