GLP-1 Drugs and Weight-Loss

What are GLP-1 agonists?

Glucagon-like peptide one agonists (GLP-1) drugs were originally developed and prescribed for the treatment of diabetes. However, their effect on limiting appetite and promoting weight-loss has made them popular with many who struggle to maintain a healthy weight through lifestyle change (creating a modest caloric restriction via diet and exercise).

How effective are they?

There is still a need for more research but recent research showed that over a 17-month period, more than half of the participants lost 5% of their initial body weight (10 pounds for a 200 pound person) and about a fifth of the participants lost 10% of their starting body weight (20 pounds for a 200 pound person). Importantly, it should be noted that diet and exercise are still critical recommendations for long-term weight-management - even for those taking GLP-1 drugs. And weight-loss results from drugs alone are very similar to those of the National Diabetes Prevention Program (the most researched lifestyle change program in the United States) which averages 7% weight-loss over 12-months.    

Which drugs are approved for weight-loss and how are they prescribed?

Currently Wegovy (aka Ozempic), Saxenda and Mounjaro are approved for the treatment of obesity. These injectable drugs (daily or weekly) are not available over the counter, a prescription is necessary. To qualify, people need to have a BMI of ≥30 or a BMI of ≥27 with a weight-related health condition (pre-diabetes, heart disease, etc.). 

How do they work?

They work by mimicking the action of a naturally occurring hormone called glucagon-like peptide 1. Following a meal, when blood sugar begins to rise, GLP-1 also rises and binds to its receptors in the pancreas, stimulating the production and release of insulin, which lowers blood sugar by facilitating its movement from the bloodstream into the tissues of the body. GLP-1 agonist drugs imitate naturally occuring GLP-1 in the body, lowering blood sugar in a similar manner. In addition, these drugs appear to slow the movement/digestion of food from the stomach to the small intestine. This results in feeling fuller, longer, reducing your appetite and thoughts of food. 

Do these drugs need to be taken long-term (over a lifetime)?

Likely, yes. These drugs are being viewed by most in the medical community as life-long, similar to the way many people take cholesterol, blood pressure or diabetes drugs. People who stop taking GLP-1 drugs regain weight very quickly. According to one recent study, people regained two-thirds of the weight they lost once they stopped taking the drug. So, much like most lifestyle interventions and surgeries, people have to keep with it if they want to see long-term results.

Are diet and exercise still necessary?

Yes. Lifestyle change, using diet and exercise to burn a few more calories each day than a person eats, is still the #1 recommendation for weight-loss and weight-management. In fact, GLP-1 medications recommend that people incorporate lifestyle changes while using them. It is also important to realize that exercise comes with additional health and longevity benefits (additional healthy years, significantly reduced risk of many chronic diseases, improved mental health, etc.)..

What are the risks?

For most people, these drugs appear to be relatively safe. The drugs have been approved for the treatment of diabetes for several years. The most common side effects include: nausea, diarrhea and vomiting. GLP-1 drugs are not recommended for the following groups: people who are pregnant, those with digestive conditions like inflammatory bowel disease (IBD), or those with a family history of pancreas or thyroid issues. It is important to note that the long-term impact of these drugs on weight-loss is not completely clear and one troubling finding is that individuals taking GLP-1 drugs see a very rapid loss of muscle mass. Studies have shown that approximately half of the weight lost by GLP-1 users is not fat, but muscle. This can have serious long-term implications on your metabolic rate and ability to lose weight, musculo-skeletal health, general health (risk of type 2 diabetes, heart disease, etc.) and even a person’s longevity.

How can Prism help?

Monitor body composition and ditch BMI and the scale. Regular body composition scans allow people to monitor fat and muscle changes while on a GLP-1 program. If excessive muscle or fat loss occurs, they will be aware and can seek assistance from their physician or other healthcare professional to make the appropriate changes to their GLP-1, diet and exercise plans for their health.

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References

• Understanding Obesity | Wegovy: https://www.wegovy.com/tools-and-resources/understanding-obesity.html
• Tomkin G, et al. Treatment of type 2 diabetes, lifestyle, GLP1 agonists and DPP4 inhibitors. World J Diabetes. 2014; Oct 15; 5(5): 636-650. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4138587/
• Chodzko-Zajko W, et al. American College of Sports Medicine Position Stand. Exercise and physical activity for older adults. Med Sci Sports Exer. 2009 Jul;41(7):1510-30.
• Mayo Clinic. GLP-1 agonists: Diabetes drugs and weight loss: https://www.mayoclinic.org/diseases-conditions/type-2-diabetes/expert-answers/byetta/faq-20057955
• Forbes health. GLP-1 agonists for weight loss: What you need to know: https://www.forbes.com/health/weight-loss/glp-1-agonists/
• Wilding JPH, et al. Weight Regain and Cardiometabolic Effects After Withdrawal of Semaglutide: The STEP 1 Trial Extension. Diabetes Obes Metab. 2022;24(8):1553-1564.
• American Diabetes Association. Standards of medical care in diabetes — 2020. Diabetes Care. 2020; doi:10.2337/dc20-SINT.
• Dungan K, et al. Glucagon-like peptide 1 receptor agonists for the treatment of type 2 diabetes mellitus. https://www.uptodate.com/contents/search. Accessed April 10, 2020.
• Boyle JG, et al. Cardiovascular benefits of GLP-1 agonists in type 2 diabetes: A comparative review. Clinical Science. 2018; doi:10.1042/CS20171299.

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