GLP-1 Medications

By: Meaghan Orellana, Nutrition and Dietetics Student

What are GLP-1 Medications?

You have probably heard of celebrities, friends or family members taking this new weight loss drug with common names like Ozempic or Wegovy etc. But what are they, how do they work and most importantly, are they safe? GLP-1 stands for Glucagon Like Peptide-1, which is a hormone in the body that plays a role in appetite and glucose regulation. These medications contain GLP-1 receptor agonists (GLP-1 RA), which mimic the GLP-1 hormone naturally found in our body, to turn on the appetite and glucose regulating pathways. (Moiz et al., 2025)

How Do They Work?

GLP-1 RAs work in a few ways; appetite suppression, delayed gastric emptying, improved glucose dependent insulin secretion, glucagon suppression, improved energy expenditure and lipid metabolism. 

In the brain, GLP-1 RAs bind to GLP-1 receptors to stimulate pathways that increase satiety, reduce hunger and decrease the reward response for consuming high calorie, appetizing foods.  They also impact our hunger and satiety hormones leptin and ghrelin helping you feel full for longer. The hormones Peptide YY and Cholecystokinin secreted in the gastrointestinal tract are amplified by GLP-1 RA to slow gastric emptying and prolong feelings of fullness.

The activation of GLP-1 receptors in the pancreas by GLP-1 RAs improves the secretion of insulin in response to elevated blood sugar levels after eating. Insulin acts by allowing cells to take circulating glucose from the blood stream in for use of energy. Thus decreasing blood glucose levels. Without adequate insulin, the cells are not able to receive glucose and will signal the brain to consume more energy. This stabilizing effect inhibits overeating by reducing excessive hunger cues. At the same time, the release of the hormone glucagon, which signals glucose production in the body, is decreased. Maintaining fasting glucose levels within a normal range. 

GLP-1 RAs improve the metabolism of lipids. This in combination with regulated glucose levels allows the body to optimize the utilization of fat stores for energy and decrease the storage of excess calories as fat. The metabolism is increased though thermogenesis, enhanced by GLP-1 RAs. (Moiz et al., 2025)

Weight Loss Benefits 

A meta-analysis investigating the efficacy of GLP-1 RAs such as Wegovy and Ozempic, found 85.8% of obese patients taking the medication lost >5% total body weight compared to 34.7% of patients on placebo after a year's follow up. 33.4% of obese patients taking the medication lost >20% total body weight compared to 2.2% of those in placebo (Moiz et al., 2024). This significant weight loss can help people stay motivated to keep up with lifestyle changes and reduce barriers to exercise. Some concerns have been raised about bone density changes with GLP-1 RAs. Research conducted has found that when it is taken as a treatment with exercise, there is not a significant decrease in bone mass (Birk et al., 2024). 

Considerations

Adverse effects noted include gastrointestinal upset such as nausea, vomiting and abdominal pain, but was reported to be mild in severity and duration (Tan et al., 2022). However, with the use of GLP-1 RAs being used for weight loss still being relatively new, the long-term health effects have not been studied. Since these medications work in part by suppressing appetite, there is a risk of malnutrition. There is also a risk of subsequent weight gain from increased caloric intake once the medication is stopped, if lifestyle habits are not changed. One meta-analysis concluded that the average 11.85% weight loss found on GLP-1 RA medication would not be as high if not for concurrent exercise and low calorie diet, emphasizing the need of lifestyle changes for optimal results (Tan et al., 2022).

Changes in muscle mass are also a concern for both GLP-1 RAs and combination GLP/GIP medication such as Zepbound. Zepbound has been shown to have less muscle loss than GLP-1 RAs. However, the rate of muscle loss in both medications

over a 72 week period is equivalent to 20 years of age related muscle loss at 3% a year. This is in part due to the rapid drop in overall body weight. Mitigation of muscle loss is seen in people who do resistance training while on the medication. This emphasizes the need for quality nutrition and implementation of exercise while taking these medications to prevent adverse effects. (Mechanick et al. 2024)

While the efficacy in weight loss is impressive, with such all other weight loss medications, healthy lifestyle changes including diet, exercise, stress management, and improved sleep quality are necessary for long term weight loss maintenance and bone health. 

How We Can Help You 

To help you maximize your results and maintain them long-term, RAW Functional Nutrition, partnered with Coastal Fitness Center can provide you with comprehensive support.

Our personalized programs include:

• Nutritional counseling: Get a custom nutrition plan designed to complement your medication and support your health goals.

• Fitness training: Choose from one-on-one or group training to build muscle, boost your metabolism, improve your overall fitness and reduce the risk of excessive muscle loss.

• Biometric body scanning: Track your progress with detailed scans that measure total fat mass, muscle mass, bone density, protein levels, and more. 

• Accountability check-ins: Stay on track with regular support to help you reach your goals and sustain your results even after you've finished your treatment.

References:

1. Moiz, A. et al., (2025) Mechanisms of GLP-1 Receptor Agonist-Induced Weight Loss: A Review of Central and Peripheral Pathways in Appetite and Energy Regulation. The American Journal of Medicine, vol. 138, no. 6, 31 Jan. 2025, www.sciencedirect.com/science/article/pii/S0002934325000592?via%3Dihub  https://doi.org/10.1016/j.amjmed.2025.01.021. 

2. Moiz, A. et al., (2024). Long-Term Efficacy and Safety of Once-Weekly Semaglutide for Weight Loss in Patients Without Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. The American Journal of Cardiology, 222, 121–130. https://doi.org/10.1016/j.amjcard.2024.04.041 

3. Birk, S. et al., (2024). Bone Health After Exercise Alone, GLP-1 Receptor Agonist Treatment, or Combination Treatment. JAMA Network Open, 7(6), e2416775–e2416775. https://doi.org/10.1001/jamanetworkopen.2024.16775