Editorial note: this article is for general information only. It is not medical advice, and it does not promote or recommend any medicine. HerbaShape.ch is an independent Herbalife Member; our products are food supplements and meal options, not medicines, and Herbalife does not sponsor, endorse or promote any prescription medicine, including GLP-1 medications. Always follow your prescriber’s advice.
Why everyone is talking about GLP-1 medications
Over the last few years, GLP-1 receptor agonist medications — names you may know include Ozempic and Wegovy (semaglutide) and Mounjaro (tirzepatide) — have changed how medically supervised weight loss is managed in Switzerland and around the world. Prescribed alongside a reduced-calorie diet and more physical activity, they work primarily by reducing appetite: you feel full sooner, hunger quietens down, and you naturally eat much less. Clinical trials have reported average weight reductions of around 15% with semaglutide (STEP 1, New England Journal of Medicine, 2021) and up to about 21% with tirzepatide (SURMOUNT-1, NEJM, 2022).
Those numbers explain the attention. But eating dramatically less creates a nutrition challenge that deserves far more attention than it usually gets.
The catch: not everything you lose is fat
When researchers measured body composition in these trials, a significant share of the weight lost was lean mass — including muscle — not just fat. Across studies, roughly 25–40% of total weight lost came from lean tissue (STEP 1 body-composition sub-study; SURMOUNT-1 body-composition analysis, Diabetes, Obesity and Metabolism, 2025; Prado et al., The Lancet Diabetes & Endocrinology, 2024).
Muscle is what keeps you strong, mobile and metabolically active. Losing it makes everyday life harder — and makes it easier to regain fat later, because muscle is a major driver of the calories your body burns at rest.
What happens when treatment stops
The second uncomfortable finding: in the STEP 1 extension study (2022), people who stopped semaglutide regained, on average, two-thirds of the weight they had lost within one year. In SURMOUNT-4 (JAMA, 2024), 4 in 5 participants who switched to placebo regained more than a quarter of their lost weight.
Researchers draw a clear lesson: the medication is a tool, not the whole answer. Lasting results depend on the nutrition and lifestyle habits you build during treatment.
What the experts recommend: protein first
In 2025, four major American clinical societies (the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society) published a joint advisory on nutrition during GLP-1 therapy. The headline recommendations:
- Protein: around 1.2–1.6 g per kilogram of body weight per day during active weight loss — a practical target of 80–120 g daily for most adults, spread across the day;
- Resistance exercise 2–3 times a week — protein and training together are what protect muscle;
- Nutrient-dense, minimally processed foods, because when total food intake drops by 16–39%, vitamins and minerals drop with it — studies have flagged vitamin D, iron and calcium as common gaps;
- Small, frequent meals and plenty of fluids, which also helps with the digestive side effects (nausea, early fullness, constipation) commonly reported during dose escalation.
What to eat: a practical framework for a small appetite
The hardest part is arithmetic: how do you fit 100 g of protein and full micronutrition into a day when you genuinely aren’t hungry? Clinicians suggest building every day around four habits.
1. Protein at every meal — before anything else
- Aim for 25–35 g of protein per meal: eggs, quark or skyr, poultry, fish, tofu, pulses, or a high-protein shake when solid food feels like too much.
- Eat the protein portion of your plate first — appetite may run out before the plate does.
2. Fluids and fibre, every day
- Drink 1.5–2 litres of fluid daily; sip between meals rather than gulping with them if fullness is an issue.
- Keep fibre coming — vegetables, oats, seeds or a fibre drink — to support digestion and help with the constipation many people report.
3. Small, nutrient-dense meals
- Three small meals plus one or two protein-rich snacks usually beat two large meals you can’t finish.
- Make every bite count: when you can only eat a little, sugary or heavily processed extras crowd out nutrients you actually need.
4. Mind the micronutrient gaps
- With food intake down by a third or more, vitamin D, iron, calcium and B-vitamins are the usual shortfalls — nutrient-dense foods first, and a well-chosen supplement can help fill the rest.
This is exactly where well-formulated protein shakes, fortified meal-replacement options and fibre drinks can play a supporting role — compact, measured nutrition that doesn’t require a big appetite. If you’d like ready-made options, we’ve put together a dedicated Muscle & Protein Support range — high-protein shakes, micronutrients, fibre and hydration, organised into simple daily plans for during and after your journey.
The bottom line
A GLP-1 medication changes how much you eat — it doesn’t decide what you eat. That part is yours, and it determines how much muscle you keep and what remains once treatment ends. Protect your protein, keep moving, cover your micronutrients, and build habits that will still be there the day the prescriptions stop. Your future self will thank you twice: once for the weight lost, and once for the muscle kept.
Frequently asked questions
How much protein do I need on a GLP-1 medication?
Clinical guidance suggests around 1.2–1.6 g per kilogram of body weight per day during active weight loss — for most adults, 80–120 g spread over the day. Your doctor or dietitian can personalise this for you.
Can I avoid losing muscle?
You can limit it. Studies consistently point to the same pair: enough daily protein plus resistance training 2–3 times a week. Neither works as well alone.
What helps with nausea and early fullness?
Smaller, more frequent meals, eating slowly, gentler low-fat foods and sipping fluids between meals are the strategies clinicians mention most. If side effects persist, speak to your prescriber — don’t adjust anything on your own.
Do I still need vitamins and minerals if I’m eating so little?
Arguably more than ever: eating 16–39% less means proportionally fewer micronutrients. Prioritise nutrient-dense foods, and consider fortified shakes or supplements to help close the gap — you’ll find our full range of high-protein and micronutrient options in the shop. Food supplements complement a balanced diet; they don’t replace it.
Key references
- Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). NEJM 2021.
- Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). NEJM 2022.
- Look M et al. Body composition changes during weight reduction with tirzepatide (SURMOUNT-1 sub-study). Diabetes Obes Metab 2025.
- Wilding JPH et al. Weight regain after withdrawal of semaglutide: STEP 1 trial extension. Diabetes Obes Metab 2022.
- Aronne LJ et al. Continued Treatment With Tirzepatide for Maintenance of Weight Reduction (SURMOUNT-4). JAMA 2024.
- Mozaffarian D et al. Nutritional priorities to support GLP-1 therapy for obesity: joint advisory. Obesity Pillars 2025.
- Prado CM et al. Muscle matters: the effects of medically induced weight loss on skeletal muscle. Lancet Diabetes Endocrinol 2024.
This article does not constitute medical advice. If you are using or considering a prescribed weight-loss medication, all decisions about your treatment belong with you and your doctor or specialist. Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle.