What’s the Best BMI Range for GLP1-s?

If you were to believe all the marketing and influencer hype around GLP-1 drugs, including Wegovy and Zepbound, you might be led to believe that they are a panacea for every BMI and every patient who needs to lose weight. However, if you dig deeper into the data, you start to understand precisely what GLP-1s are helpful for. Before we continue, it’s important to mention that GLP-1s are an exceptional advancement in the treatment of obesity. With the assistance of these drugs, whether used before or after other interventions or on their own, patients can lose significant body weight and dramatically improve their health. In this article, we will discuss the sweet spot for patients on GLP-1s in relation to BMI and when they should be used as an adjunct rather than a primary treatment.

General thoughts on BMI and GLP-1s

As a rough guide, GLP-1s are best suited for patients with a BMI of 27.5-40. As a primary weight-loss tool, many patients can expect to lose between 15 and 25% of their body weight. This is fantastic within that BMI range and can improve or resolve many of the diseases associated with excess weight. However, beyond this number, it’s unlikely that patients will be able to lose enough weight to get as healthy as we and they expect.

Weight regain after stopping GLP-1s

Another consideration is the patient’s ability and willingness to modify their diet and exercise to maintain weight loss long after quitting GLP-1s. A recent study showed that patients using older-generation weight loss drugs may regain most, if not all, of their weight within the first year. With newer-generation GLP-1s, patients may regain weight within 2 years of stopping the medication. To that end, patients need to work closely with their primary care physician or weight-loss specialist to understand what’s necessary to ensure long-term success and avoid recidivism.

GLP-1 in preparation for surgery

Another important use for GLP-1s is as preparation for an upcoming surgery. In elective or semi-elective procedures, most surgeons try to avoid operating on patients with a BMI of much greater than 40. This can include hernia surgeries, orthopedic surgeries, and other procedures that may not be needed immediately. There is some leeway to this. For example, a patient who is actively losing weight and is approaching the 42 or 43 BMI level may be considered for surgery. Otherwise, GLP-1 agonists can be very effective in helping these patients lose enough weight to make surgery safer and more effective. If we take hernia surgery as an example, it’s essential to understand that the preoperative and postoperative risks of surgery are significantly increased with excess weight. Anesthesia becomes more dangerous, and the risk of infection and poor wound healing increases dramatically with excess weight. Even the risk of hernia recurrence increases with BMI. To that end, unless the hernia is severe, for example, if the small intestine is stuck in the hernia defect, weight loss is indicated before correction. For many patients over 40 years old with a BMI of 45, a bariatric procedure may be most suitable. Still, we understand that some patients are resistant to surgery, and GLP-1s may be an alternative to get them into a safer BMI range.

Pre- and post-bariatric surgery

It may sound counterintuitive, but GLP-1s can be a lifesaver before and after bariatric surgery. Before, GLP-1s may help patients with a very high BMI to shrink their liver for safer surgery, as well as reduce the likelihood of complications. After surgery, many patients may benefit from GLP-1 medications if they are well tolerated, and if they aren’t losing as much weight as they expected.

A patient with diabetes

GLP-1s are nothing new, and many patients don’t realize that GLP-1s in the form of drugs like Mounjaro and Ozempic have been around for many, many years to treat type 2 diabetes. And indeed, one side effect of these diabetes drugs are weight loss, hence the FDA approval for that indication. Patients with poorly controlled diabetes can benefit from a dramatic reduction in blood sugar and weight loss with GLP-1 therapy; therefore, even patients below the minimum BMI threshold for GLP-1 as a weight-loss treatment can benefit from the same active ingredient.

Side effects

Of course, the use of GLP-1s largely depends on the tolerability of their side effects, and almost every drug has some degree of these. GLP-1s have plenty of known issues, including gallbladder and pancreatic disease, gastroparesis, and reports of blindness in a small number of people with diabetic retinopathy, as well as an increased risk of depression and anxiety, and potentially even suicidal ideation (some of these reports need to be substantiated). These side effects do not affect everyone equally, so to that end, patients who will benefit and don’t have immediate contraindications should speak to their doctor about such complications. However, any of these complications usually lead to the cessation of the medication, and of course, other weight loss and weight maintenance discussions need to be had.

What are the alternatives?

Today, we have ever more effective and safer procedures available to patients with obesity, including endoscopic and surgical bariatric options. Endoscopy, which is performed entirely through the mouth and esophagus, is indicated in a small subset of patients and typically results in 15 to 20% body weight loss, similar to GLP-1s. Bariatric surgery, on the other hand, is still the best and most effective option for patients with morbid obesity, especially those with a BMI of 40 or above. Patients today have more options than ever before, including gastric sleeve, gastric bypass, duodenal switch, and SADI, each of which is exceptionally effective depending on a patient’s particular circumstances.

Of course, the decision to take GLP-1s, undergo endoscopy, or have bariatric surgery is an intensely personal one that can be made with loved ones and the guidance of a qualified weight-loss specialist.

To that end, patients can contact our office to learn more about their weight loss options and suitability for GLP-1s versus other weight-loss interventions.