gastric bypass vs. gastric sleeve
Bariatric Procedures
Gastric Bypass vs. Gastric Sleeve: Which Bariatric Procedure is Better?

The gastric bypass vs. gastric sleeve is a standard comparison of procedures. Both weight loss surgery procedures will effectively reduce weight and help patients live healthier. Aside from the obvious weight loss benefits, the bypass and the sleeve also create a metabolic and hormonal impact that improves and cures many weight-related medical problems, including diabetes, hypertension, sleep apnea, and high cholesterol. In this article, we will compare the gastric bypass vs. gastric sleeve to make the best decision for your health.

The gastric bypass and the gastric sleeve are excellent options for patients with a body mass index between the mid-30s and upper-40s. The sleeve is traditionally recommended for patients with a BMI between 35 and 45, while patients with a BMI between 40 and 50 see better results with the gastric bypass. 

Although both the gastric bypass and the gastric sleeve will help you lose weight, some differences must be noted, including the method in which they are performed and how they assist with weight loss. 

The Gastric Bypass

The gastric bypass, more formally known as the Roux-en-Y (RNY) gastric bypass, is a procedure in which we alter the intestines’ anatomy and therefore change the path of the food. The procedure works by creating a small stomach about the size of an egg, which will then directly connect to a piece of the small intestine, bypassing the main stomach (hence the name gastric bypass). During the gastric bypass procedure, the surgeon will also shorten the small intestines by about 30%. 

As a result, patients will feel full faster, even when only eating about half the food they used to consume. And since weight gain results from the overconsumption of calories relative to the amount burned, the gastric bypass works to encourage weight loss by restricting the number of calories consumed.

The Gastric Sleeve

The gastric sleeve, otherwise known as the Vertical Sleeve Gastrectomy (VSG), is a procedure in which the size and the shape of the stomach are changed. 

The vertical sleeve gastrectomy involves placing a tube through the mouth into the stomach along the lesser curve. The surgeon will divide the fat attachments along the greater curve of the stomach. Then, using laparoscopic staplers, the surgeon will divide the stomach along the tube, beginning on the lower edge of the stomach (near the pylorus) to the upper edge (near the esophagus). The surgeon will remove about 70 to 80% of the stomach, leaving a banana-shaped pouch. Unlike the gastric bypass, the sleeve will not alter how food travels through your intestines. 

Preparing for Weight Loss Surgery
Preparing for Weight Loss Surgery Guide
Deciding to have weight loss surgery can be an overwhelming decision. In this guide, we break down all the details you need to consider when evaluating your various options for weight loss.
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The Gastric Bypass vs. Gastric Sleeve

Expected Weight Loss

When comparing the gastric bypass vs. gastric sleeve, most patients want to know the expected weight loss. The gastric bypass has an average of 70 to 75% excess weight loss, whereas the gastric sleeve has an average of 60 to 65% excess weight loss. 

It is essential to understand that when we as surgeons refer to “excess weight,” we are not talking about total weight. Excess weight loss is a percentage of your excess body weight. For example, if you are 200 pounds and your goal is 100 pounds, then you have 100 pounds of excess weight. The gastric bypass is more likely to help you lose a greater percentage of your excess weight than the gastric sleeve. 

Health Impact

Aside from weight loss, we also want to look at the health benefits and risks of the gastric bypass vs. gastric sleeve. Due to the effectiveness of weight loss that the gastric bypass has, this procedure has better odds of curing diabetes and has some degree of protection from redeveloping diabetes in the future. 

The gastric bypass is also advantageous for patients who experience gastroesophageal reflux disease (GERD). We do not recommend the Gastric Sleeve for patients with GERD because it could cause severe symptoms that are extremely difficult to control, aside from having a revision. 

On the contrary, because the gastric bypass is more involved, there is a slightly higher risk of complications. Similarly, the intestinal bypass will result in the malabsorption of nutrients, leading to nutritional deficiencies if you do not take your bariatric vitamins.

The gastric sleeve is the least aggressive of staple bariatric procedures (bypass, sleeve, and duodenal switch), and it is easier to advance your diet after this procedure.


When you visit your bariatric surgeon for your initial visit, we will review your weight, medical history, and any health conditions that will help you decide the gastric bypass vs. gastric sleeve. We will also want to understand your weight loss expectations to help you choose the best weight loss procedure to fit your lifestyle. However, we encourage you to continue your research to understand what bariatric procedure is best for you. 

Donald Maynard, MD, FACS
Dr. Donald Maynard is a board-certified bariatric and general surgeon with over 20 years of experience in the medical field. Dr. Maynard started the practice Surgical Associates of Metro Atlanta (SAMA Bariatrics) where he specializes in general and bariatric surgery.
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