On a Weight-Loss Jab? Here's How to Keep Your Muscle (and Your Strength)

Few health stories have moved as fast as GLP-1 medicines. Semaglutide (sold under brand names including Ozempic and Wegovy) and newer drugs like tirzepatide have gone from diabetes clinics to celebrity gossip to dinner-table chat. Health media from Stockholm to London now asks a sharper question: not just how much weight you lose, but how well you lose it.

What the medicines do

GLP-1 receptor agonists mimic a gut hormone that helps regulate blood sugar and appetite. They slow stomach emptying and make you feel full sooner and for longer. For people with obesity, the results in trials have been striking. In the STEP 1 trial, published in the New England Journal of Medicine in 2021 (Wilding and colleagues), adults with overweight or obesity who took weekly semaglutide 2.4 mg alongside lifestyle support lost an average of about 15% of their body weight over 68 weeks, compared with about 2.4% on placebo.

The HN24 take these are prescription medicines with real side effects, including nausea, constipation and, rarely, more serious problems. Use them under a doctor's care, and never from an unregulated online source. In South Africa, buy only from a registered pharmacy with a prescription. Counterfeit "jabs" are a real risk.

The muscle problem

When you lose weight by any means (diet, surgery or medication), some of what you lose is lean mass: muscle, plus water and other non-fat tissue. Body-composition data from GLP-1 trials suggest that a meaningful share of the weight lost can be lean mass. And because these drugs cut appetite so strongly, it's easy to under-eat protein without noticing.

Why it matters:

• Muscle keeps you strong, mobile and steady on your feet as you age.
• Muscle is a major site of blood sugar disposal.
• Losing a lot of muscle can make weight easier to regain if you later stop the drug.

For him

Treat it like a cut

If you've ever done a bodybuilding-style "cut", you already know the playbook: eat in a calorie deficit while lifting heavy and eating plenty of protein, so the loss comes mostly from fat. The same applies here. A GLP-1 medicine takes care of the deficit. Your job is to protect the engine.

For her

Strength is the real glow-up

For women, especially in midlife when muscle and bone are already under pressure from falling oestrogen, the stakes are higher. Losing weight while also losing strength and bone isn't the transformation anyone wants. Lifting turns weight loss into a body-composition change, so you end up fitter, not just smaller.

The muscle-protection plan

1. Lift at least twice a week. Follow the WHO and NHS guideline of muscle-strengthening work for all major muscle groups on two or more days. Squats, hinges, pushes, pulls and carries, with the load progressing over time. See our Lift for Longevity starter plan.

2. Prioritise protein at every meal. With a smaller appetite, eat protein first. Aim for a palm-to-a-palm-and-a-half portion at each meal: eggs, fish, chicken, yoghurt, cottage cheese or legumes. Many sports dietitians use about 1.2 to 1.6 g per kilogram of body weight as a working range when dieting. Ask your doctor or dietitian what's right for you, especially if you have kidney disease.

3. Don't drop too low on calories. Very low intake speeds up muscle loss and makes training miserable. If you're struggling to eat enough, tell your prescriber, because doses can be adjusted.

4. Keep moving every day. Walking (try interval walking) supports heart health and helps maintain fitness without adding much fatigue.

5. Watch the basics. Fibre and fluids help with the constipation these medicines commonly cause. Limit alcohol, which adds calories and can make nausea worse.

6. Measure what matters. Track strength in the gym and your waist measurement, not just the scale. If your lifts are holding steady or going up while your weight falls, you're doing it right.

What about stopping?

Trials have shown that many people regain a substantial amount of weight after stopping semaglutide. That's another reason to build strength, protein and activity habits while you're on the medication. They're the part that stays when the prescription ends.

A sample day on a small appetite

When you can only face small meals, every bite has to work harder. Here's one way to structure the day:

• Breakfast: plain Greek yoghurt or maas with berries and a spoon of seeds
• Mid-morning: a boiled egg or two
• Lunch: a small tuna, chicken or bean salad, eaten protein first
• Afternoon: a glass of milk or a protein shake, which is useful if solid food is hard to face
• Dinner: a palm-sized portion of fish, chicken or lentils with veg, and a small serving of starch

Smaller, more frequent meals and eating slowly can also help with nausea.

The scale tells you how much you've lost. Your strength tells you what you've lost.

Questions to ask your doctor

• How much protein should I aim for, given my health conditions?
• Should I have my body composition, blood sugar or kidney function checked during treatment?
• What should I do if I can't keep food down?
• What's the plan for the long term, including if or when I stop?

Not just a vanity issue

For people living with obesity, type 2 diabetes or heart disease, these medicines can be genuinely life-changing, and nobody should be shamed for using them. The aim here isn't to discourage treatment. It's to make sure the result is a stronger, healthier body that lasts beyond the prescription.