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The revolution began with a lizard. The Gila monster – a venomous desert dweller – held a secret in its saliva that would transform our understanding of weight loss.

The Gila monster’s saliva contains compounds that mimic GLP-1, a glucagon-like peptide hormone your intestines naturally produce. This discovery would lead to medications that represent the largest shift in weight management since the 1990s.

“We’re not just seeing weight loss. We’re uncovering how metabolism connects to addiction, behaviour, and chronic disease in ways we never imagined,” says Dr Anton Meyberg, a pulmonologist and specialist physician practising at Netcare Linksfield Hospital.

For Dr Meyberg, this isn’t just about prescribing the latest medication. He is exploring how our understanding of obesity, exercise, and breakthrough medications is transforming the way we approach lasting physical change.

Dr Anton Meyberg - Pulmonologist and specialist physician practising at Netcare Linksfield Hospital

 

The biology of being trapped For decades, the weight-loss formula seemed simple: eat less, move more. Push harder. Not losing weight according to this outdated paradigm implied that those who struggled with obesity simply lacked discipline. The real revolution began in 2022, when obesity was officially reclassified as a complex chronic disease. “Deep in your brain, a region called the hypothalamus controls appetite and fat storage. When this system is disrupted, it creates a cruel feedback loop – the more weight you gain, the hungrier you feel. Your hormones conspire against you. Your metabolism slows. It’s like trying to climb out of a hole while someone keeps making it deeper,” explains Dr Meyberg. “This isn’t metaphorical. The numbers are staggering: 2.5 billion people worldwide are overweight, with one billion classified as obese. That includes 350 million children. We’re facing a pandemic that seldom makes headlines, yet it’s reshaping the health of entire generations. Understanding obesity as a disease isn’t about making excuses. It’s about finding solutions that actually work,” he adds. The weight loss puzzle “Physical inactivity increases your chance of premature death by as much as 20 to 30%, but you don’t need to become a marathon runner overnight to start feeling the benefits of exercise. The magic number is surprisingly achievable: just 150 minutes of moderate exercise per week. That’s only 20 minutes a day. A brisk walk at lunchtime. Dancing while you cook dinner. Take the stairs instead of the lift – small changes add up. But here’s what most weight-loss advice gets wrong: exercise is just one piece of the puzzle.” “Your body doesn’t compartmentalise. Poor sleep disrupts hormones that regulate hunger. Chronic stress triggers cortisol production, which promotes fat storage. Everything connects. This holistic approach doesn’t just prevent chronic disease and manage weight – it fundamentally changes how you feel day to day,” he emphasises. Enter the game changers “GLP-1 is a natural hormone produced in the intestines that supports digestion, food processing, and metabolism. It works through multiple pathways: triggering insulin release, slowing digestion to keep you fuller for longer, reducing appetite in the brain, and decreasing inflammation throughout the body.

 

“Medications that mimic this hormone have transformed weight management. What makes them revolutionary is the timing of their action; GLP-1s act before you even take a bite of food, inducing a sense of fullness. They have both pre-ingestion and post-ingestion effects because they reduce your appetite – you actually don't feel like eating,” notes Dr Meyberg.

The plot twists nobody expected
These medications – initially used to treat diabetes – began revealing connections nobody anticipated.

“The ripple effects are noteworthy: a 50% reduction in alcohol intake, decreased compulsive behaviours like gambling, and improved fertility in women with polycystic ovarian syndrome. Most striking is the significant reduction in cardiovascular deaths,” says Dr Meyberg.

Researchers are now exploring their potential for Parkinson's and Alzheimer's disease, since GLP-1s are produced in both the intestines and the brain. “They aren’t just weight-loss drugs – they’re revealing connections between metabolism, behaviour, and overall health,” he adds.

Each generation of new medication has brought new capabilities:

• First generation (semaglutide): Delays gastric emptying and suppresses appetite
• Second generation (tirzepatide): Does the above with a dual receptor approach and enhances insulin secretion
• Third generation (retatrutide): As a triple receptor, it blocks the above and increases energy expenditure while enhancing fat-burning
• Fourth generation: In development; includes muscle-preserving components to prevent excessive loss of facial volume.

Caution and consultation
These medications come with serious reality checks. “No medicine is without side effects. Over 90% of users initially experience nausea, vomiting or diarrhoea. More concerning: if you stop taking them, the weight often returns just as fast as it left. The survival mechanisms that programme our bodies to store fat have long memories. These aren’t casual weight-loss aids – they are powerful medications and the potential risks and benefits must be carefully discussed and evaluated,” cautions Dr Meyberg.

He points out that in South Africa, medical aids don’t cover these prescribed medications yet as they are not defined as a chronic medication.

“If your BMI is under 25, stay away. These medications are for people facing significant weight-related health threats, not for dropping a few kilos before summer. They require careful medical screening and proper technique. You really need to push fluids to prevent kidney damage. Inject in a different area each time, and hold the skin firmly to ensure proper placement.

“Here’s what we’re really talking about: a powerful tool that works best when combined with the basics – better sleep, real food, regular movement, and stress management. Without these changes, you’re essentially renting your weight loss.”

“We’re witnessing something profound: medications that reveal how deeply connected our metabolic health is to everything else. They’re teaching us that obesity is a complex biological puzzle. The question isn’t whether these medications work – they do. The question is whether we’re ready to use them wisely.

“The weight-loss revolution nobody saw coming isn’t just about new drugs or finally recognising obesity as a disease. The future of weight management isn’t about finding a magic bullet. It’s about understanding our bodies well enough to work with them, not against them. These medications might be part of that future, but they’re not the whole story,” concludes Dr Meyberg.

Ends

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