If you have been reading the news lately, chances are you've heard the names Ozempic, Wegovy or GLP-1 medications. These prescription drugs have captured public attention in a way no weight loss treatment has before. However, many clients still have questions about them and are hesitant to start because of the possible side effects. People also seem to be curious to know where diet and eating plans fit in and if they are necessary to get results. This article will go through some of the pros and cons of using GLP medications compared to traditional weight loss strategies.
What Are Weight Loss Medications?
Weight loss medications — most commonly GLP receptor agonists like semaglutide (sold as Ozempic for diabetes management and Wegovy for weight management) and tirzepatide (known as Mounjaro) work by mimicking hormones produced naturally in the gut after eating. They slow digestion, reduce appetite and help regulate blood sugar levels.
These drugs require a prescription from your doctor and ongoing reviews. They are not available over the counter and are generally only prescribed for people with a BMI of 30 or above, or 27 or above with an obesity-related health condition.
Pros of Weight Loss Medications
Weight loss results. A 2025 meta-analysis that included 47 randomised controlled trials and involving over 23,000 patients found that GLP-1 receptor agonists produced around 15% weight loss along with reductions in waist circumference.
Benefits beyond weight loss. A report from 2023 found that GLP-1 medications led to a 20% reduction in the risk of heart attack and stroke in people with excess weight and cardiovascular disease.
Reduction in appetite and food noise. Many people on these medications report a significant reduction in the persistent thoughts around food which they find helps them to make better foods choices.
Cons of Weight Loss Medications
They require ongoing use. This is perhaps the most important consideration. The landmark STEP 1 trial extension found that one year after stopping semaglutide, participants regained two-thirds of their weight loss, with cardiometabolic markers returning toward baseline. A 2026 systematic review found that people regained weight faster after stopping weight loss medications than after ending behavioural programs (approximately 0.4 kg per month on average), with projections suggesting a return to starting weight within 18 months to two years.
Side effects. Gastrointestinal symptoms including nausea, vomiting and constipation are among the most commonly reported side effects, particularly in the early stages of treatment. While these often ease over time, they are a reason some people discontinue use.
Cost and access. These medications usually cost around $400 - $700 per month on a private prescription (assuming you are not being prescribed it for diabetes). This is a significant investment considering the potential length of time required to reach weight loss goals.
They are not a standalone solution. National medical guidelines recommend that these medications should be used alongside dietary and lifestyle changes and not a replacement for them. Without building sustainable habits alongside the medication, maintaining weight after stopping becomes significantly harder.
What Are Meal Replacement Shakes?
Meal replacement shakes (such as Tony Ferguson) are specifically formulated drinks with a focus on providing adequate protein and nutrients within a much smaller number of calories than you would eat in a typical meal. It is expected people will replace one to two meals per day as part of a structured weight management approach.
It's worth noting the difference between a meal replacement and a protein shake. A true meal replacement has enough added vitamins and minerals to be a reasonable substitute for a full meal. A protein shake on the other hand is typically designed to provide additional protein in a drink which is easy to consume.
Pros of Meal Replacement Shakes
Evidence-backed weight loss. A systematic review examined 23 randomised controlled trials with nearly 8,000 participants and found that programs incorporating meal replacements were equally or more effective than other diets and supports. The result that really stood out was in those people using meal replacements with an enhanced level of support lost. It was reported that they lost 6kg more than those on alternative diets with regular support over 1 year. Support may include seeing a dietitian for diet and behaviour strategies or regular weight checks and encouragement from your GP.
Simplicity and structure. Removing the decision of what to eat for one or two meals a day can significantly reduce decision fatigue. This can be particularly helpful for maintaining consistency when life gets busy.
Accessible without a prescription. Meal replacement programs can typically be started without a medical referral, making them more immediately accessible. They are also considerably more affordable than weight loss medications.
Supports habit building. Unlike medication, using a structured meal replacement program over time offers the opportunity to develop a greater awareness of portion sizes, reduce overeating habits and build a more consistent food routine. These are skills that can support long-term weight maintenance.
Nutritional consistency. Meal replacements provide a reliable baseline level of nutrients, reducing the risk of nutrient gaps that can occur on highly restricted diets.
Cons of Meal Replacement Shakes
Increases in hunger. The reduction in overall energy may be too much if you have an active job or lots of physical activity as it can leave you feeling very hungry and at the mercy of sugar cravings.
Taste and variety. Some people find the taste or texture of shakes difficult to tolerate. Variety of flavours and versions (bar vs soup vs shake) may help to keep things interesting.
Not appropriate for everyone. Meal replacements may not be suitable during pregnancy, breastfeeding or for individuals with certain medical conditions. A dietitian or GP should be consulted before starting, particularly for those with a history of disordered eating.
Key Differences and Who Might Consider Each Option
These two approaches are not direct competitors. Sometimes they can be used together as an easy way to obtain nutrients when appetite is very low or separately to help maintain weight loss after using GLP medications.
Weight loss medication may be more helpful if someone has a very high BMI, has a long history of unsuccessful attempts at weight loss or they have a health condition such as type 2 diabetes or osteoarthritis and are working with a doctor to manage their weight medically.
Meal replacement programs may suit those looking for a structured and easily accessible starting point for weight management, particularly when the goal is building sustainable eating habits over time.
Both approaches work best when combined with behavioural support, dietary education and some form of physical activity. These are the fundamentals that the research consistently shows matter most in the long run.
Conclusion
There is no single best approach to weight management. What works is what is safe, sustainable and suited to your needs and lifestyle. Don’t be afraid to reach out to your trusted health care professional to discuss your options and help you decide what may suit you best.
If you're considering weight loss medication, speak with your GP before you make a decision. If you're exploring a structured meal replacement program, an Accredited Practising Dietitian can help you find an approach that fits your health goals, lifestyle and nutritional needs.
Sustainable weight management isn't about finding the fastest route — it's about finding one you can actually stay on.
