The Pros and Cons of Weight Loss Surgery

Gastric Bypass Surgery Is One Type of Weight Loss Surgery. Martin J Cook/Moment/Getty Images

Have you ever considered a surgical procedure for weight loss? It helps to know what is currently available, what is most effective and what the risks are before making such a major, potentially life-changing decision.

What Is Bariatric Surgery?

Let’s start with the basics. The term “bariatric surgery” applies to a number of surgical procedures that have been developed to treat obesity and surgically induce weight loss.

These include gastric bypass, gastric banding, and gastric sleeve (sleeve gastrectomy) procedures, among others, which have been developed for the surgical treatment of obesity.

Who Is a Candidate for Bariatric Surgery?

According to the latest obesity guidelines released by the American Heart Association (AHA), the American College of Cardiology (ACC), and The Obesity Society (TOS), bariatric surgery may be an option for adult patients who meet certain criteria.

These criteria include a body mass index (BMI) of 40 or greater, or a BMI of 35 or greater in a patient who has other medical conditions (known as “comorbid conditions”) caused by obesity.

The obesity guideline writing committee did not find sufficient evidence to recommend bariatric surgery for patients who have BMIs that fall below these cutpoints.

The guideline further advises primary care doctors and others caring for patients with obesity with high BMI to try “behavioral treatment with or without pharmacotherapy” first, and then if this has not worked along with other diet and lifestyle measures to achieve sufficient weight loss, bariatric surgery may be considered.

What Are Some of the Most Common Types of Bariatric Surgery?

Most people have heard of gastric bypass surgery, which has been around a long time, but is now not being done as commonly as some of the other procedures covered here. Basically, gastric bypass surgery helps patients lose weight by surgically shrinking the size of the stomach—thus causing one to feel full on less food.

There are several forms of gastric bypass surgery, including the Roux (pronounced “roo”)-en-Y gastric bypass (RGB) procedure and biliopancreatic diversion with duodenal switch (also known as extensive gastric bypass). RGB is the most common gastric bypass operation performed in the United States. All gastric bypass operations are performed under general anesthesia.

Gastric banding—commonly referred to as a “lap-band” when done laparoscopically—is another form of bariatric surgery. With the gastric band procedure, which is usually performed laparoscopically, a band is placed around the stomach, dividing the stomach into two pouches: a small upper pouch located above the band, and a larger lower pouch below the band.

The small pouch limits the amount of food that one can eat at any single sitting, and thus causes a feeling of fullness with less food.

The band can be adjusted by injecting or removing saline from it, thereby decreasing or increasing the size of the opening between the two parts of the stomach.

The band is removable and does not permanently alter the anatomy of the stomach or digestive tract.

Gastric banding falls under the category of “restrictive” weight-loss surgical procedures, because it reduces, or restricts, the effective capacity of the stomach to receive food.

Another surgical procedure is sleeve gastrectomy, or gastric sleeve, which reduces food intake and induces weight loss. In this procedure, approximately 60 percent of the stomach is removed (usually laparoscopically), such that the remaining portion of the stomach takes on the shape of a tube or sleeve.

Because the stomach is smaller after the operation, the gastric sleeve patient will feel fuller faster and with less food. For these reasons, the gastric sleeve procedure another “restrictive” type of bariatric surgery.

How Effective Is Bariatric Surgery?

Researchers are now investigating the effectiveness of these surgical weight loss procedures and it appears that the degree of effectiveness depends upon the specific procedure being performed.

In a systematic review of studies that have been published to date, one group of researchers found that all published gastric bypass studies reported at least 50 percent weight loss, with an average excess weight loss of 65.7 percent. The rate of Type 2 Diabetes reportedly dropped by 66.7 percent. There was also a reported 38.2 percent reduction in the rate of hypertension (high blood pressure). Additionally, the studies reported remission rates of 60.4 percent for hyperlipidemia (high cholesterol) following gastric bypass.

For the gastric band procedure (also known as the lap band), in the aforementioned systematic review of available published studies, the investigators found that reported excess weight loss was 45 percent on average, with a reduction in type 2 diabetes rates of 28.6 percent. The reduction in the rate of hypertension was 17.4 percent with the gastric band, and the reduction in hyperlipidemia was 22.7 percent.

For the gastric sleeve procedure, also known as sleeve gastrectomy, research has found it to result in an average 65% excess weight loss.

So, initial evidence points to gastric bypass and gastric sleeve procedures being more effective than gastric banding in terms of a magnitude of weight loss.

Additionally, gastric bypass appears to be more effective than gastric banding for reducing the rates of chronic diseases that are associated with obesity, such as type 2 diabetes, high blood pressure, and high cholesterol.

In spite of the evidence thus far, however, longer-term follow-up studies are needed, as no studies of bariatric surgery appear to report outcomes beyond five years. Thus, although the initial weight loss numbers are known, what is not known is how much weight loss is maintained over seven or ten years or even longer.

What Are Some of the Benefits of Bariatric Surgery?

Beyond the obvious benefits of weight loss, bariatric surgery has been shown to improve disorders that are related to obesity, including diabetes, cholesterol levels, blood pressure and even mental health.

A meta-analysis that reviewed the available bariatric surgery literature found 68 publications that reported on mental health conditions in the context of bariatric surgery.

According to the study authors, “Among patients seeking and undergoing bariatric surgery, the most common mental health conditions … were depression and binge eating disorder.”

Specifically, 19 percent of patients were found to have depression and 17 percent were found to have binge eating disorder.

While neither depression nor binge eating disorder was found to be consistently associated with differences in weight outcomes following surgery, it appears that bariatric surgery itself had favorable effects on patients with depression.

The researchers found that bariatric surgery was consistently associated with lower rates of depression after the operation. Bariatric surgery was also associated with a decrease in the severity of the symptoms of depression.

The study authors concluded that “mental health conditions are common among bariatric surgery patients—in particular, depression and binge eating disorder.” They also noted the support for “an association between bariatric surgery and lower rates of depression postoperatively [after surgery].”

Another study found that, among patients with both obesity and type 2 diabetes, bariatric surgery combined with lifestyle interventions like exercise and healthy eating was more effective in fighting diabetes than was lifestyle intervention alone (without bariatric surgery).

What Is the Most Popular Weight Loss Surgery?

Over the past couple of years, the popularity of the gastric sleeve procedure (also known as sleeve gastrectomy) has skyrocketed due to its effectiveness and safety as compared with other procedures.

In fact, according to Bariatric Surgery Source, the gastric sleeve procedure now appears to be overtaking gastric bypass as the new “gold standard” procedure.

What Are the Risks?

Bariatric surgery, in general, has been found to be slightly more risky than cholecystectomy (gall bladder removal), but less risky than appendectomy, colon surgery, small bowel surgery and stomach (gastric) surgery.

Bariatric surgery has also been found to be much less risky than pancreatic, liver (hepatic) or esophageal surgery.

Specifically, for elective surgical weight-loss procedures, mortality falls in the 0.05 percent - 0.2 percent range, way below 1 percent.

Certain risks are common to all surgical operations that require anesthesia, such as the possibility for heart or lung problems and even death (which is rare). For bariatric surgery, in particular, there are complications that can develop over the longer term, such as bowel obstruction, gallstones, hernias, stomach perforation, ulcers, malnutrition, vomiting and dumping syndrome (in which food empties into the small intestine too quickly, resulting in diarrhea, nausea, and vomiting).

As with most bariatric surgery procedures, patients will need to be followed closely for the rest of their lives to monitor for vitamin and mineral deficiencies. Most patients will require vitamin supplementation and laboratory (blood test) monitoring on a regular basis, as many if not all of the bariatric surgery procedures cause changes in how the body absorbs certain vitamins and nutrients.

Patients who have had bariatric surgery must still be strict about their diet and lifestyle habits as it is not uncommon to gain weight once more even after the surgery if the recommended lifestyle changes, which include both diet and exercise, are not followed vigilantly.


Jensen MD, Ryan DH, Apovian CM, et al. 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society [published online November 27, 2013]. J Am Coll Cardiol.

Jensen MD, Ryan DH. New obesity guidelines: promise and potential. JAMA 2014; 311:23-24.

Schauer PR, Bhatt DL, Kirwan JP, Wolski K, et al. Bariatric surgery versus intensive medical therapy for diabetes—3-year outcomes. N Engl J Med 2014; 370:2002-13.

Puzziferri N, Roshek TB, Mayo HG, et al. Long-term follow-up after bariatric surgery: a systematic review. JAMA 2014;312:934-942.

Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery: a systematic review and meta-analysis. JAMA 2004;292:1724-1737.

Arteburn DE, Fisher DP. The current state of the evidence for bariatric surgery. Editorial. JAMA 2014;312:898-899.

Puzziferri N, Roshek TB, Mayo HG, et al. Long-term follow-up after bariatric surgery: a systematic review. JAMA 2014;312:934-942.

Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery: a systematic review and meta-analysis. JAMA 2004;292:1724-1737.

Arteburn DE, Fisher DP. The current state of the evidence for bariatric surgery. Editorial. JAMA 2014;312:898-899.

Dawes AJ, Maggard-Gibbons M, Maher AR, et al. Mental health conditions among patients seeking and undergoing bariatric surgery: a meta-analysis. JAMA 2016;315:150-163.

Arterburn D, McCulloch D. Bariatric surgery for type 2 diabetes: getting closer to the long-term goal. JAMA 2016;315:1276-77.

Courcoulas AP, Belle SH, Neiberg RH, Pierson SK, et al. Three-year outcomes of bariatric surgery vs lifestyle intervention for type 2 diabetes mellitus treatment: a randomized clinical trial. JAMA Surg 2015;150:931-940.

Continue Reading