Weight Loss Drug vs. Bariatric Surgery: Which One Is Better?

Fact checked by Nick Blackmer

The success of Ozempic and Wegovy appears to be ushering in a revolution in obesity and type 2 diabetes treatment. Each new iteration of experimental weight loss drugs seems better at helping patients with obesity shed stubborn pounds and keep their diabetes in check.

Promising outcomes from clinical trials showing weight reductions of more than 20% have inspired bold claims that medications could soon trump bariatric surgery, the gold standard for obesity treatment since the 1950s.

In fact, the opposite may be true, said Marina Kurian, MD, FASMBS, president of the American Society for Metabolic and Bariatric Surgery.

“We actually think we’re going to see an increase in patients coming to surgery,” Kurian told Verywell.

New weight loss drugs borrow from the bariatric surgery playbook, increasing levels of key digestive hormones that control appetite and insulin production. Ozempic and Mounjaro, which are indicated for type 2 diabetes, seem to be as effective at controlling blood sugar as surgery is. But patients who get surgery typically lose between 40% and 70% of their excess weight. Wegovy, a version of Ozempic that is labeled for weight loss, doesn’t even come close to that.

As people become more accustomed to weight loss medications, Kurian said there is an improved understanding of obesity as a chronic condition and how the treatments work.

“All these medical therapies to help lose weight will kind of open the public’s eyes to say, ‘Hey, this is a safe treatment. I have side effects with medications. I could have some side effects with surgery, but surgery is safe, and it will make me feel like I’m on the medication,” Kurian said.

Related: What's the Difference Between Ozempic, Wegovy, and Mounjaro?

Why Is Bariatric Surgery the Gold Standard for Treating Obesity?

Bariatric surgery refers to several types of procedures used to restrict the stomach and reshape the gastrointestinal tract so it can hold less food and absorb fewer nutrients.

Gastric sleeve surgery removes about three-quarters of the stomach and sculpts it into a banana-sized sleeve. A Roux-en-Y operation involves shrinking the stomach to the size of a walnut and rearranging the small intestine to limit how many calories are absorbed. The adjustable gastric band restricts the stomach size without permanently dividing it.

Not only do these procedures cause immense weight loss. They can also treat conditions including diabetes, high blood pressure, sleep apnea, and heart disease, and reduce the risk of developing arthritis, cancer, strokes, and more. A large 2021 review found that weight loss surgery decreased the risk of all-cause mortality by 50%. People with diabetes who underwent surgery saw an extra nine years of life, on average.

Despite decades of data showing the long-term benefits of bariatric surgery, scientists aren’t totally sure why it’s so effective. Restructuring digestive organs and transecting nerves appears to change the levels of hormones, bile acids, and gut microbiota that signal the brain when the body is ready for more food, said Daniel Drucker, MD, FRCPC, an endocrinologist and clinician-scientist at the Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital in Toronto.

“It’s probably like an orchestra. You have the end result, which is this great symphony or tremendous weight loss. But there are multiple different instruments contributing to the fantastic result, just like there are multiple different mechanisms all contributing to telling the person they’re just not as hungry as they used to be,” Drucker told Verywell.

Some of those underlying mechanisms inspired the class of weight loss medications that now enjoy the limelight.

Related: Gastric Sleeve vs. Gastric Bypass: Which Is Right for You?

How Do Weight Loss Drugs Compare to Bariatric Surgery?

Ozempic and Wegovy mimic the digestive hormone glucagon-like peptide-1 (GLP-1), which boosts insulin levels, increases the feeling of fullness, and slows the emptying of the stomach. Mounjaro and other drugs in development mimic GLP-1 and one or more additional hormones that play a role in controlling appetite and digestion following bariatric surgery.

Early data from drugmaker Eli Lilly shows that retatrutide, a new GLP-1 receptor agonist drug, may help patients lose more than 24% of their body weight.

But scientists aren’t yet sure if medical therapy can deliver the same long-term outcomes as bariatric surgery.

“I’ve been a big supporter of GLP-1-based therapy for 35 years. But if you look at the data objectively, you’d say that bariatric surgery has more data for long-lasting, durable improvements in health,” Drucker said. “We can’t put the cart before the horse and say, ‘Well, just because we’re starting to get better weight loss, that means we’re now on par with bariatric surgery.’ We have a lot more information to obtain and to understand before we can make that type of comparison.”

To confidently compare GLP-1s and bariatric surgery, scientists will need to do a randomized clinical trial looking at the long-term effects and safety of each approach, as well as how they each fit into an individual’s lifestyle.

In the meantime, researchers are seeking to understand the health effects of GLP-1s beyond weight loss and blood sugar control. For instance, Lilly is studying how semaglutide might be able to treat heart failure with preserved ejection fraction, diabetic kidney disease, fatty liver disease, and peripheral arterial disease.

Related: What Happens to Your Body When You Stop Taking Ozempic?

Can You Combine Weight Loss Drugs and Surgery?

Although bariatric surgery has been proven safe and effective over several decades, only about 1% of people who are eligible for a procedure choose to get it. Some patients don’t consider it necessary to treat their obesity, Kurian said, while others are nervous about getting surgery or can’t get the operation covered by insurance.

Kurian said she doesn’t see medication approaching the level of efficacy she sees with bariatric surgery any time soon. Still, she welcomes the addition of anti-obesity medications.

“The question shouldn’t be one or the other, but how and when can the two modalities work together?” Kurian said.

Having two highly effective tools in the arsenal opens new possibilities for providers to help patients reach the normal or overweight range, if that’s a goal of theirs, Kurian said.

For instance, providers may prescribe a GLP-1 drug to help people lose enough weight to minimize the risk of complications from surgery. Alternatively, for patients with weight recurrence in the years after getting bariatric surgery, providers may add a medication that will take off 5% or 10% more to help them manage and maintain their weight long-term.

“Obesity is such a chronic disease. What we know about obesity and its causes is just really the tip of the iceberg and the majority is submerged underwater,” Kurian said. “Doing more than one treatment in the same patient and tailoring it can really be far more effective to ensure successful and sustained weight loss.”

Related: New Weight Loss Drugs Are on the Way That Could Upstage Wegovy and Ozempic

What Are the Pros and Cons of Weight Loss Drugs and Bariatric Surgery?

The reality of undergoing surgery or committing to medication can be vastly different.

Surgery can cost $15,000 to $25,000. But bariatric procedures are typically covered by Medicare and private insurance if a patient meets certain criteria. To see success from GLP-1s, meanwhile, patients may have to shell out $800 to $1,400 a month indefinitely.

Bariatric surgeries are typically done laparoscopically or robotically, making them minimally invasive. It often takes a few days to be discharged and four to six weeks to recover. Although the risk of complications is low, some patients experience gallbladder issues, dumping syndrome, and nutritional deficiencies.

GLP-1 drugs are noninvasive, but they must be taken for life, or else the patient’s body weight could come right back. The medications also tend to come with a host of uncomfortable side effects, like nausea, vomiting, and diarrhea, which can sometimes be persistent enough that people will stop taking them.

If someone taking a weight loss medication experiences uncomfortable side effects, they can simply stop taking it. But reversing a surgery or managing complications can be more challenging.

Scientists have studied the safety of GLP-1 drugs for diabetes treatment for 18 years. But data on drugs like Ozempic and Wegovy has only been explicitly studied in patients with obesity for a couple of years.

“This is really a new era in the new medical treatment of obesity,” Drucker said. “We should always be humble about what we don’t know and what potential rare side effects there might be, and we should continue to study the safety of these medications as the new ones become available. We shouldn’t take for granted that we really understand their profile and their long-term safety.”

Read Next: Should You Take Ozempic When You’re Over 65?

What This Means For You

People who have a body mass index (BMI) of 35 or more with no comorbidities, or 30 or more with a comorbidity, like diabetes, are eligible for bariatric surgery. If you’re considering weight loss surgery or medical treatment, speak with a team an interdisciplinary team of providers versed in obesity medicine and lifestyle management.