GLP-1: The Next Frontier in Weight Loss

A science-backed look at how GLP-1 weight loss works, what to expect, and the risks you should know.

For years, pharmacy shelves have been packed with thermogenic fat burners promising to “boost metabolism” and “burn fat fast.” But the real shift in weight loss has arrived through modern medicine — and it’s changing everything.

GLP-1 agonists are leading this new era, offering a science-backed route to long-term weight control that works very differently from old-school fat burners.

Where GLP-1 medications began

GLP-1 drugs were first created to treat type 2 diabetes because they help regulate blood sugar. In the early 1990s, Dr John Eng discovered a blood-sugar-regulating hormone in the venom of the Gila monster, a lizard from the US Southwest. This breakthrough led to the development of exenatide, the first GLP-1 drug.

These medications were originally meant to stimulate insulin production for diabetes management. But researchers noticed a consistent side effect: people lost weight. The drugs helped regulate appetite and digestion, revealing that obesity often stems from biology rather than willpower. That discovery paved the way for GLP-1 agonists to be approved specifically for weight loss.

A global surge in popularity

With around 3 billion people worldwide classified as overweight or obese, effective solutions are in high demand. Most people who lose weight regain much of it,  around two-thirds within a year, and over 80 percent within five years according to a major meta-analysis.

So it’s no surprise GLP-1 medications have exploded in use. A 2025 KFF Health Tracking Poll found that one in five adults in the US has already taken a GLP-1 drug, and one in eight still uses them.

The risks to watch out for

While GLP-1s can be transformative, they are not without drawbacks. Because these medications reduce appetite so effectively, many people unintentionally eat too little, increasing the risk of losing muscle mass along with fat. Muscle is essential for metabolic health, strength and long-term weight maintenance, so inadequate protein and nutrient intake or a lack of resistance training can lead to weakness and a slower metabolism. 

Another concern is rebound weight gain. Once treatment stops or doses are reduced, appetite and cravings often return, and the body may quickly regain weight, sometimes even surpassing the original starting point. Sustained lifestyle changes are vital to help protect muscle and support weight stability during and after treatment.

Some clinical studies report that a substantial portion of the weight lost under GLP-1 therapy is not fat — but lean mass (which includes muscle). For example, one analysis of trials found that between 39 % and 40 % of total weight lost on GLP-1 treatments was lean mass. 

The loss of muscle mass during weight loss with GLP-1s may pose serious risks, particularly for older patients: decreased muscle mass can impair posture, mobility, and increase the risk of frailty or even mortality. 

How GLP-1s turn down hunger

GLP-1 medications mimic the body’s natural glucagon-like peptide-1 hormone, which boosts feelings of fullness and reduces hunger. One of the most noticeable physical changes is slowed gastric emptying; food sits in your stomach far longer, making you feel full on much smaller portions.

If you try to overeat, the pressure in your stomach signals discomfort, often nausea, stopping you in your tracks. These drugs also activate receptors in the brain’s hypothalamus, the centre that manages appetite and energy balance. They send a clear chemical message of fullness, even without a huge meal.

For people living with obesity, this helps override a biological system that often pushes the body back up to a higher “set point.”

Turning down the cravings

Perhaps the most revolutionary part: GLP-1s also dampen hedonic hunger, the dopamine-driven desire for sugary or fatty treats when you’re tired, sad, or stressed.

Because GLP-1 receptors also sit in the brain’s reward pathways, the usual dopamine “hit” from high-calorie foods becomes weaker. This effect, called hedonic de-escalation, also shows early promise in supporting addiction treatment, including food, drug, and alcohol addiction.

Input over output

Thermogenic fat burners try to increase calorie burn, often by only 50–100 calories a day, about half a biscuit. GLP-1s tackle the other side of the equation: calorie intake.

By quieting intense hunger signals, they make it far easier to naturally maintain a calorie deficit without depending on strict willpower or punishing exercise routines. Still, diet and exercise remain important for the best results.

Diet and lifestyle considerations

Weight loss from GLP-1 medications includes both fat and muscle, so protein intake is essential. Aim for 20–30 g of protein per meal from foods like chicken, fish, tofu, beans, or chickpeas. Moderately active people should target 1.6 g of protein per kg of body weight daily, increasing to 2.2 g/kg/day if training intensely. Combined with strength training, this helps protect – and even build – muscle.

Because appetite is reduced, highly active individuals need a more deliberate fuelling strategy. Grazing on smaller, nutrient-dense meals and snacks can help maintain steady energy. Choose complex carbohydrates like quinoa, millet, rolled oats, sweet potatoes, and brown rice. Healthy fats like olive oil and avocado support stable energy levels too.

To avoid nausea caused by slowed digestion, skip fried or high-fat foods, eat smaller portions, and space meals out. Bland staples like crackers or whole-grain toast can help if your stomach feels unsettled. Heartburn is also common, avoid lying down after eating and keep portions small.

Hydration is crucial. GLP-1s can blunt thirst, increasing dehydration, nausea, and constipation. Aim for two to three litres of fluid daily and include water-rich foods such as cucumber, watermelon, and soups. Fibre from oats, apples, vegetables, and nuts also helps keep digestion regular. Extreme calorie restriction can worsen dehydration and lead to fatigue, nutrient deficiencies, or kidney stress.

Beware counterfeit products

Rising demand has triggered a black market for fake GLP-1 medications, especially on social media. South Africa’s Health Products Regulatory Authority (SAHPRA) recently warned consumers to avoid unregistered versions and highlighted cases of companies falsely claiming links to SAHPRA or major South African retailers.

The future of weight loss

GLP-1 drugs mark a major turning point in how we understand and treat obesity. We are moving from a “willpower” mindset to recognising weight as a chronic biological condition that can be managed, much like asthma or hypertension, with effective medical treatment.

Yet it is important not to view GLP-1s as a stand-alone solution. They work best when paired with the foundations of long-term health: balanced nutrition, regular physical activity, good sleep, and sustainable lifestyle habits. Medication can support the process, but a healthy lifestyle remains the number one priority.

These treatments signal the beginning of a new, science-driven era in weight loss, not a replacement for the daily choices that keep the body strong, resilient and well.

Disclaimer: The information in this article is intended for general information and education only. It is not a substitute for professional medical advice, diagnosis or treatment.

Always consult your doctor or another qualified healthcare professional if you have any questions about a medical condition, symptoms, treatment options or medication. Never ignore professional medical advice or delay seeking it because of something you have read in this article.

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