The Science Behind GLP-1s: How it Targets Appetite and Metabolism

As different weight-management routines and medications become more accessible, it is crucial for those on their weight-loss journey to understand the science behind these new options. Terminologies like glucagon-like peptide-1 receptor agonists, homeostasis, and improved lipid metabolism can be confusing for people outside the medical field, making the usage of weight-management medications daunting. However, once patients can comprehend how these medications affect the body, this knowledge lifts the mysterious veil of complicated jargon and simplifies the entire process.

What is GLP-1?

The most important aspect to understand about weight-loss medications is knowing what GLP-1 is. GLP-1, which stands for Glucagon-like peptide-1, is a naturally occurring hormone produced in the small intestine that assists digestion and metabolism, stimulates insulin secretion, and regulates gastric emptying. Basically, GLP-1 helps keep the gut and intestines working correctly to maintain healthy blood sugar levels as well as affecting the part of the brain that creates satiety (or feeling “full”) and curbs cravings, which is all important when maintaining or getting to a healthy weight. GLP-1 antagonists are the synthetic version of the hormone; they are created to mimic the same properties of the naturally produced hormone and are usually administered via injection.

How does GLP-1 cause weight loss?

Since GLP-1 assists in the digestive process, it is integral for weight loss and management. GLP-1 antagonists trigger the release of the hormone, not only making us feel fuller for longer but also assisting the GLP-1 receptors in the brain, effectively reducing cravings. The synthetic versions of GLP-1 amplify a natural process already happening within the body, promoting increased weight loss and improved metabolism/appetite regulation. 

Here are the four main weight-loss properties of GLP-1:

• Delays gastric emptying: GLP-1 helps control how long the body takes to digest and empty the food in the stomach. The slower the body takes to empty the stomach, the less it craves more food — slow digestion means less glucose (the scientific name for sugar) is released into the blood.
• Increases feelings of satiety: Satiety describes the feeling of fullness, which is the opposite of hunger. This feeling is actually controlled not by the gut but by the brain, which also has GLP-1 receptors. 
• Counteracts glucagon secretion: Glucagon is the hormone that raises blood sugar levels when they are low. Sometimes, glucagon can release too much glucose into the blood system, and GLP-1 will suppress unnecessary spikes in blood sugar.
• Improves insulin levels and sensitivity: Insulin is a crucial hormone that turns food into energy. When insulin levels are too low, they increase the risk of Type 2 diabetes and negatively impact blood sugar levels. GLP-1 improves the body’s insulin production.

What triggers the release of GLP-1?

Food is usually the natural way to trigger the release of GLP-1, especially in a high protein, high fiber diet that includes healthy fats. The gastric intestinal tract receives the food and not only digests it but also responds by signaling to the brain a feeling of satiety, telling us when to stop eating. L-cells are the cells that secrete the hormone, making this whole process run smoothly. Exercise is another way to trigger GLP-1. Weight management medications can release the hormone without solely using food to activate L-cells by binding to the body’s GLP-1 receptors, thus successfully lowering the risk of heart disease, stroke, and kidney disease, as well as improving cholesterol and blood pressure. 

Will I regain weight after stopping GLP-1?

GLP-1 is a necessary hormone for the body's daily functions, which means it’s vital to maintain healthy GLP-1 secretion throughout your life. Increasing GLP-1 levels is not a magic one-time weight loss solution; stopping GLP-1 or falling back into bad dietary and exercise habits will inevitably lead to weight gain. As bariatric endoscopist and obesity medicine physician Dr. Daniel B. Maselli, MD, ABOM, told Healthline: “These medications are treatments and not cures…While these GLP-1 medications can mute those obesity-promoting pathways or heighten obesity-fighting pathways, those pathways, fundamentally, still exist. So when you remove the GLP-1 medication, that patient is set back on a course of weight increase.” The best way to maintain the results from improved GLP-1 levels is to maintain a healthy lifestyle focused on clean eating and exercise. 

If you’re interested in GLP-1 medications for weight loss, Dr. Barrett Plastic Surgery in Beverly Hills offers consultations for more information. Call us at (310) 398-2648 or fill out this virtual consultation form, and we will contact you as soon as possible. We’re excited for you to take this next step! To learn more about Barrett Plastic Surgery, subscribe to our blog and follow us on social media at TikTok, Instagram, Realself, and YouTube for updates.