Since their approval as weight loss drugs in 2021, Ozempic, Wegovy, and other forms of semaglutide have gained significant attention. This has fueled curiosity about the drug’s mechanism, its ideal candidates, and its long-term safety. Initially approved in 2017 for type 2 diabetes treatment, semaglutide is a glucagon-like peptide -1 receptor agonist (GLP-1 RA) that mimics a hormone called GLP-1. GLP-1 assists in regulating blood sugar and curbing appetite.
GLP-1 RAs are remarkably effective for weight loss, offering a promising solution for individuals battling obesity or those managing weight for non-medical reasons. These medications are proving to be reasonably safe, though long-term effects are uncertain due to limited use. Nevertheless, GLP-1 RAs offer significant benefits for metabolic health and quality of life.
Despite their effectiveness, these medications are not without their downsides. Many people experience unpleasant side effects such as nausea, vomiting, diarrhea, and fatigue. Additionally, GLP-1 agonists are prescription-only drugs, meaning they are not accessible to everyone and can come with a high price tag.
Should you take GLP-1 RAs for weight loss?
As a Registered Dietitian, I believe effective weight management encompasses a comprehensive lifestyle change that includes maintaining a healthy, well-balanced diet, leading an active lifestyle, achieving quality sleep, and implementing stress management techniques. It is also important to acknowledge that personal body composition goals, as well as cognitive and social factors, play significant roles in an individual’s motivation for weight loss. Consequently, GLP-1 RAs should be made accessible to those pursuing weight management for a variety of reasons, including health improvement and aesthetic considerations. Just as we accept medications for improving mental health or quality of life, the motivation behind weight loss—whether for health or personal satisfaction—deserves the same consideration.
Ultimately, an informed choice is key; clients should be aware of the risks and benefits in order to align decisions with their goals and values. Embracing this perspective can help reduce the stigma around obesity treatment and support an inclusive approach to weight management.
Primary care teams should take a holistic approach by considering all aspects of health, including physical, mental, and emotional well-being, before making recommendations for medication use.
How Weight Loss Medication Works
GLP-1 receptor agonists (GLP-1 RA) are like special messengers in your body that help manage weight by influencing how your brain, digestive system, and blood sugar work optimally. GLP-1 RA helps you feel fuller, slows digestion, and maintains stable blood sugar, all aiding in weight management.
Brain
In the central nervous system, GLP-1 RA modulates appetite by activating the brain’s hunger control center within the hypothalamus, leading to enhanced satiety and reduced food intake. Many say it helps lessen the “food noise.”
Digestive System
In the digestive system, GLP-1 RA slows gastric emptying, keeping food in the stomach longer and promoting prolonged fullness. This results in less snacking between meals and reduced food intake at each meal.
Blood Sugar Regulation
GLP-1 RA regulates blood sugar by enhancing insulin use and secretion, reducing glucagon release, and delaying stomach emptying. This control aids weight management by lowering fat storage and moderating post-meal glucose absorption.
Benefits to Cardiovascular Health and Brain Health
Beyond aiding weight loss, GLP-1 RAs offer substantial cardiovascular benefits. They help control blood sugar, support weight loss, and decrease blood pressure and inflammation, all of which contribute to a healthier heart. They directly improve the health of blood vessels and help prevent the buildup of harmful plaque, lowering the chances of heart attacks, strokes, and other heart-related issues. Additionally, GLP-1s may protect brain health by fighting against insulin resistance and inflammation linked to obesity, which could reduce the risk of memory loss and dementia.
History of Weight Loss Medication
The foundation of GLP-1 therapy traces back to the 1980s when researchers at Harvard Medical School identified GLP-1 as an incretin hormone. Shortly after, the first GLP-1 receptor agonist (GLP-1 RA) was developed by pharmaceutical companies, assisting in its commercialization.
The use of GLP-1 RAs in diabetes management marks a significant advancement in endocrinology, tracing back to the early 2000s. GLP-1 RAs transitioned from diabetes management to obesity treatment as researchers noticed significant weight loss. Once seen as a side effect, weight loss became central to research and development. In 2021, the FDA approved semaglutide for weight management.
The future of GLP-1 RAs looks promising, with research aimed at enhancing weight reduction, minimizing side effects, and improving delivery methods. New combinations with other peptides, such as GIP agonists, are emerging. As understanding of metabolic diseases grows, peptide applications are expected to offer more effective and personalized treatments.
As a Registered Dietitian, I have nearly two decades of experience working with these treatments. At the University of Calgary’s Diabetes Research Clinic, I served as the Diabetes Research Lead, focusing on Victoza (Liraglutide) from 2007 to 2011. During this time, we observed remarkable weight loss outcomes, along with glycemic control and significantly reduced our clients’ need for diabetes medications.
Peptides for Weight Management: Single and Dual
In Canada, there are several prescription medications available for weight management in single and dual formulations.
Semaglutide (Wegovy, Ozempic, Rybelsus)
Semaglutides, like Ozempic, are approved for treating type 2 diabetes, but are often used off-label for weight loss. Wegovy, a higher-dose formulation, is approved for weight management and is available for individuals with obesity or those who are overweight with comorbid conditions. Both Ozempic and Wegovy come as a weekly injection, while Rybelsus is a daily pill. It has been noted that injectables better suppress appetite. Studies show an average weight loss of 15% over 68 weeks from any of these options.
Tirzepatide (Zepbound, Mounjaro)
Tirzepatide, is a novel ‘dual’ GLP-1 RA with a GIP receptor agonist. The GIP component enhances insulin secretion and fat metabolism, while the GLP-1 RA surpasses the dose provided in Semaglutide to more effectively improve satiety and glucose control. Studies show 15-22.5% weight loss over 72 weeks.
In late 2023, the FDA approved tirzepatide for chronic weight management in adults, but it has not yet been submitted to Health Canada. Currently, tirzepatide is approved in Canada for type 2 diabetes management under the brand name Mounjaro, and it is being used off-label for weight loss.
Liraglutide (Saxenda, Victoza)
Liraglutide is a ‘single’ peptide GLP-1 receptor agonist used for both type 2 diabetes under the name Victoza, and for chronic weight management under the name Saxenda. While both formulations use liraglutide, Saxenda is specifically targeted for weight loss at a higher dose than Victoza. Studies show it promotes weight loss, though it is less potent than the newer medications like Semaglutide or Tirzepatide. Research indicates an average weight loss of 8-10% over 56 weeks. Liraglutide is available in Canada.
At the time of publishing, please note that there are other GLP-1 RA’s approved for diabetes management, including: Dulaglutide (Trulicity), and exenatide (Byetta, Bydureon BCise). This is an ever evolving field, highlighting the importance of speaking with a care provider who is up to date on the most recent science and pharmaceuticals.
Alternative Oral Weight Loss Medications
Existing oral weight loss medications include Xenical and Contrave. Xenical (orlistat) is an oral medication that blocks the absorption of dietary fat, leading to its excretion, but gastrointestinal side effects, such as loose stools, often result in high discontinuation rates. Contrave (naltrexone and bupropion), works by suppressing appetite and is typically considered for individuals struggling with both obesity and emotional or binge eating, but should be monitored due to its effects on mood and mental health.
The Future of GLP-1 Receptor Agonists and Weight Loss
Emerging peptide medications are showing promising results in clinical trials for weight management, with new formulations like Retatrutide and CagriSema pushing the boundaries of weight loss therapy. Retatrutide, a triple agonist targeting GLP-1, GIP, and glucagon receptors, enhances appetite control and energy expenditure, showing significant weight loss potential. CagriSema, combining semaglutide and amylin analog cagrilintide, aims to improve satiety and fat metabolism. GLP-1 receptor agonists hold potential in aiding weight loss and improving metabolic health markers, with long-acting options and combination therapies on the horizon. Achieving sustainable weight loss is a multifaceted journey that benefits from a holistic approach with a healthcare team and a Registered Dietitian for lasting health improvements.
Collaborate with a Registered Dietitian to Support Weight Loss
Registered Dietitians play a crucial role in supporting weight loss while using these medications. Our focus goes beyond merely enhancing weight loss; we aim to preserve muscle mass, improve body composition, and promote lasting behavioural changes for enduring health benefits.
Regular visits with a dietitian help manage side-effects like gastrointestinal upset and optimize results through tailored nutrition plans. For example, we consider adequate protein intake, balanced macronutrients, and meal timing. When clients reach their goal weight and consider discontinuing medications, dietitians provide guidance to sustain weight loss by developing individualized, sustainable behaviour changes for long-term success.
Choosing to Forgo Weight Loss Medication
For clients who prefer to forgo medications, Registered Dietitians offer evidence-based strategies aimed at mimicking the effects of weight loss drugs. These strategies include promoting early satiety, increasing the metabolic rate, improving insulin sensitivity, and reducing resting blood glucose levels. They support the development of sustainable behavior changes, which are crucial for addressing issues like mindless eating or habitual snacking—with or without the aid of weight loss medications.
Registered Dietitians apply techniques that naturally support weight loss and its maintenance. This approach involves the use of dietary fiber, healthy fats, proteins, optimal meal timing, balanced macronutrient distribution, and strength training, among others. Your Registered Dietitian can customize these strategies to suit your lifestyle and nutrition preferences, ensuring they are seamlessly incorporated into your daily routine.
