Gastric Sleeve vs Gastric Bypass


You need to understand all your options before deciding on which surgical procedure is best for you between sleeve gastrectomy and gastric bypass surgeries. These two procedures both reduce hunger, are permanent and lead to a higher percentage of weight loss when compared to the laparoscopic gastric band also called the lap band.

They are also the two most common weight loss surgeries available. Although both operations are performed for obese patients to help them achieve the necessary weight loss, they differ regarding expected weight loss, mechanism of action, rapidity of weight loss, cost, complication profile and reversal of comorbid conditions. To help you choose the best surgical procedure for you, we will compare gastric sleeve surgery to gastric bypass based on the following factors

  • Mechanism of action or procedure
  • Duration and method of surgery
  • Expected weight loss
  • Speed of weight loss
  • Reversal of comorbid conditions
  • Risk

Mechanism of action

Bariatric surgeries reduce food intake or absorption of calories to induce weight loss. Gastric bypass reduces both absorption and intake of food. It does this by creating a small pouch of the of the stomach, refashioning the small intestine to bypassing the upper portion of the intestine. On the other hand, sleeve gastrectomy is solely restrictive. During this procedure, 75-80% of the stomach is removed, leaving behind a banana-like tube. The 20-25% remaining minimizes the amount of food taken in and reduces the appetite inducing hormones in the stomach.

Duration and method of surgery

The two Bariatric surgeries can either be done by laparoscopy or open surgery. Laparoscopic surgery accelerates recovery time and reduces the perioperative complications. It is a minimally invasive surgery that makes use of several small incisions in the abdomen to allow entry of the laparoscopic tools to be used. All these reasons favor the laparoscopic approach to bariatric surgery.

However, the duration for gastric sleeve surgery is less than the gastric bypass procedure. The difference between the length of stay in the hospital is not more than a day, patients tend to have to stay in the hospital after a gastric bypass surgery where gastric sleeve patients typically are released within 24 hours of surgery.


Since the reason behind both surgeries is to lose excess weight, the results of bariatric surgery are usually measured by the percentage of weight loss, the degree of resolution of comorbid conditions and the risks of complications.

Expected weight loss

Patients for gastric sleeve surgery are expected to lose between 50-70% of excess weight while those that have done gastric bypass surgery lose between 60-80% of excess weight. This loss of excess weight is usually experienced in about 12-18 months of surgery and the sustainability of weight loss for both operations is almost equal at about 50% in ten years.

Reversal of comorbid conditions

Both bariatric surgeries may lead to complete resolution or most often an improvement of comorbid conditions like osteoarthritis, diabetes mellitus, hypertension, sleep apnea, high cholesterol and high blood pressure. Studies have shown that gastric bypass patients record a relatively higher resolution of these comorbid conditions than gastric sleeve patients.


Studies have shown that gastric bypass surgery has a higher risk of complications than its fellow bariatric surgery the gastric sleeve. Leakage from staple lines and bleeding can be experienced in both surgeries.

While other complications such as anastomotic stricture, intestinal obstructions and dumping syndrome could occur after a gastric bypass surgery, they very rarely occur with gastric sleeve patients. Although patients with heartburn before surgery are often advised to choose gastric bypass surgery because gastric sleeve surgery has been shown to sometimes increase the incidence of heartburn from gastrointestinal esophageal reflux disease (GERD).

Both operations can bring about nutritional deficiencies although it is more common with gastric bypass surgery because it is both malabsorptive and restrictive. Generally, risk of death after a bariatric surge is very low at about 0.4%. However, this is slightly higher after a gastric bypass surgery.

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