How Evolving Safety Has Changed the Outlook on Bariatric, Metabolic Surgery, with Gregory Weiss, MD


Gregory Weiss, MD, provides perspective on how improved safety of these procedures has revolutionized the way clinicians view use of bariatric and metabolic surgeries as a method for inducing weight loss in people with overweight and obesity.

Gregory Weiss, MD

Gregory Weiss, MD

It has been nearly 30 years since the last consensus guidelines were published by the bariatric or weight loss surgery community back in 1991. While the original guidelines were heralded as a breakthrough in weight reduction therapy, Teresa LaMasters, MD, president of the American Society for Metabolic and Bariatric Surgery states,

It’s time for a change in thinking and in practice for the sake of patients. It is long overdue.1

There are some important differences from 1991 to now among them a more inclusive selection criterion. But before we visit the new guidelines let’s go back to 1991 see what brought us here today. While the origins of weight loss surgery can be traced back to the 1950s when the first intestinal bypasses were performed widespread use of the modern iteration of that procedure didn’t see broad acceptance and use until the late 80s and early 1990s. With an emphasis on comorbidities such as diabetes and cardiovascular disease, weight loss surgery came into its own. Initial outcomes showed promise while complications still hindered efforts to reach a larger population of obese patients.

As with most new procedures, bariatric surgery in the early years was reserved for the most extreme cases of obesity and only included patients with body mass indices (BMI) of greater than 40 or greater than 35 if they also had several comorbid obesity-related conditions. The new guidelines suggest including patients with BMI >35 and as low as 30 when metabolic diseases are present.1

Another key point in the 2022 update to bariatric guidelines is a long overdue validation of the safety and effectiveness of the collection of procedures. Central to the coming-of-age story here is the collective sentiments that:

“Metabolic and bariatric surgery is currently the most effective evidence-based treatment for obesity across all BMI classes”

“Studies with long-term follow up, published in the decades following the 1991 NIH Consensus Statement, have consistently demonstrated that metabolic and bariatric surgery produces superior weight loss outcomes compared with non-operative treatments.”

With greater than 90% of current weight loss procedures consisting of the modern Roux-en-Y Gastric Bypass and the sleeve gastrectomy, older operations have effectively been replaced with safer and more effective ones.1 While combating obesity itself is a worthwhile endeavor we are learning that weight reduction surgery dramatically changes outcomes related to metabolic diseases including diabetes and cardiovascular disease.2

A recent study by scientists at Rutgers looked at cardiovascular outcomes after bariatric surgery in obese patients with nonalcoholic fatty liver diseases (NAFLD).2 They found a striking 50% reduction in cardiovascular events such as heart attacks, chest pain, and stroke after bariatric surgery.2 The high prevalence of obesity in the United States coupled with cardiovascular disease remaining the leading cause of death for men and women in this country highlights the importance of this update and what it means for obese patients at risk.

Unfortunately, we are reaching far too few patients with obesity. Even before the inclusion criteria for bariatric surgery was broadened only 1 to 2% of the worlds eligible patient population end up getting weight reduction surgery each year.1 This statistic should give us all pause. That means that the vast majority of patients who may realize significant weight loss and freedom from life-threatening comorbidities are not being reached. The impact of doubling and then tripling the number of qualifying patients who receive weight loss surgery could have a staggering impact on so many diseases as well as real reductions in morbidity and mortality related to obesity.

The ASMBS guidelines serve as a wakeup call to all clinicians from the general practitioner to the general surgeon. We must share the benefits of weight reduction surgery with all our obese patients and have a frank discussion with them about the benefits versus the small risks of proceeding with surgery. While a concerted campaign to identify suitable patients is in order, we must be cautious not to ignore the guidelines. While bariatric surgery is by far the most effective and long-lasting weight reduction method for many, regular encouragement and lifestyle modification must still be the foundation on which we build better outcomes for our obese patient population.


  2. Elsaid MI, Li Y, Bridges JFP, Brock G, Minacapelli CD, Rustgi VK. Association of Bariatric Surgery With Cardiovascular Outcomes in Adults With Severe Obesity and Nonalcoholic Fatty Liver Disease. JAMA Netw Open. 2022;5(10):e2235003. doi:10.1001/jamanetworkopen.2022.35003
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