Obesity is a complex condition with many causes, including genetics, environmental factors, medications and lifestyle choices. Many people struggle for years to lose weight and keep it off.

Bariatric surgery and medications called GLP-1s (glucagon-like peptide-1 receptor agonists) are popular options for treating obesity. Learn about these two treatment approaches and their effectiveness at achieving weight loss goals.

Surgery vs. Injections

Bariatric surgeries: These are operations that remove or bypass part of the stomach for the purpose of losing weight and reducing levels of ghrelin, a hormone that stimulates appetite. Introduced in the 1950s, the surgical techniques have evolved over time, and several options are now available. The two main choices are:

• Laparoscopic sleeve gastrectomy, which removes 60% to 70% of the stomach and uses a stapling device to create a smaller reservoir for the stomach that is the size and shape of a banana.
• Laparoscopic gastric bypass. Instead of removing part of the stomach, this surgery reroutes a portion of the intestines to create an even smaller stomach pouch that holds about 30 milliliters, so patients feel full after eating about 4 ounces of food. This is roughly half the capacity of the stomach created through laparoscopic sleeve surgery.

Both approaches are minimally invasive, meaning they involve very small incisions and typically a single overnight stay in the hospital. In some cases, robotic surgery techniques are used.

GLP-1s: These are injectable medications that have been used since 2005 as a treatment for diabetes. In 2014, the Food and Drug Administration began to approve them for weight loss, and in recent years, more injectables have been approved and are gaining popularity as a weight loss tool. GLP-1s work by mimicking a hormone in the small intestine known as the glucagon-like peptide-1 receptor, which triggers insulin production and increases feelings of fullness.

• Weekly injections: Patients inject themselves in the fatty tissue below the skin. Common sites for injection are in the abdomen, thigh or upper arm.
• Prescriptions are required. There are several name brands available, including Ozempic, Wegovy, Zepbound and Mounjaro, as well as generics.

Eligibility Criteria: Bariatric Surgery vs. GLP-1s

Bariatric Surgery: For bariatric surgery, a person should:

• Be healthy enough for surgery. Patients must get a cardiac screening and other presurgical screenings.
• Have tried unsuccessfully to lose weight with other regimens.
• Have a body mass index (BMI) of 40 or higher — or between 35 and 40 if they also have an obesity-related condition such as sleep apnea, high blood pressure, reflux, high cholesterol, osteoarthritis or fatty liver disease.
• Receive nutrition counseling and a psychiatric evaluation before surgery.

Surgeons will take into account preexisting conditions, such as gastroesophageal reflux disease and other comorbidities to help guide patients toward the operation that is better for them. For example, patients with GERD tend to have better results with a laparoscopic gastric bypass.

If a person has too many severe chronic conditions, bariatric surgery may not be an option.

GLP-1s: To receive GLP-1s, a person must have a BMI of 30 or higher, or lower if they have a weight-related health condition like type 2 diabetes, hypertension or sleep apnea.

Weight Loss Effectiveness: Bariatric Surgery vs. GLP-1s

Bariatric surgery: People who have bariatric surgery may lose 100 pounds, or 60% to 70% of their excess body weight. Studies show that people who lose weight after bariatric surgery tend to keep most or all of it off, and have much lower occurrences of obesity-related conditions such as type 2 diabetes or heart disease. Gastric bypass, in particular, can often reverse type 2 diabetes and gastric reflux disease.

GLP-1s: These injectables are not effective for everybody, and it is not yet well known why some people have success losing weight with GLP-1s and others do not. In the most successful cases, people can lose about 30 pounds, or as much as 20% of their body weight. However, the medications work only as long as patients continue to take them. Weight gain is common if patients stop their medications.

Recovery and Side Effects After Bariatric Surgery vs. GLP-1s

Bariatric surgery: After bariatric surgery, patients are advised to eat a liquid, high-protein diet for the first week, and they may begin gentle exercise right away.

Potential side effects tend to be from the surgery itself, including nausea from the anesthesia or pain at the incision site. Rapid weight loss may lead to fatigue, so it’s important that patients follow a guided nutrition plan.

GLP-1s: Some people taking GLP-1s experience nausea, fatigue, dizziness and constipation. About 40% of patients are able to tolerate GLP-1s for extended periods of time.

Insurance and Costs of Bariatric Surgery and GLP-1s

Bariatric surgery: The cost will depend on several factors, including the type of surgery and your insurance plan. Each insurance company has different requirements that patients must meet to qualify for reimbursement for bariatric surgery. 

GLP-1s: GLP-1s are typically not covered by insurance as a weight loss treatment. Brand-name medications, such as Ozempic, Wegovy, Zepbound and Mounjaro, can cost $1,000 or more per month. Generic options are generally a little cheaper.

Some GLP-1s are approved to treat type 2 diabetes. Insurance often covers the medications for this diagnosis.

Combination Bariatric Surgery and GLP-1s

Obesity is a complex condition to treat. Some people find that combining both treatments can enhance outcomes. They may go on a GLP-1 to lose weight before bariatric surgery, or to help them continue to lose weight if they hit a plateau after the surgery.

How to Choose a Weight Loss Treatment

A first step in any weight loss plan is to talk with your primary care provider. To find the plan that is right for you:

• Determine your weight loss goals.
• Understand your current health status.
• Consider the time, recovery and cost commitments of treatment.
• Consult a weight loss specialist or bariatric surgeon.