®Sit-to-stand from a chair
Sit at the front of a sturdy chair. Without using your hands, stand up as you breathe out and sit down slowly. When it gets easier, hold a weight such as a water bottle or use a lower chair.
8–12 reps, 2–3 sets1 billion+People living with obesity worldwide (World Health Organization)
19% / 10%Average fall in fat mass and in lean tissue mass in the semaglutide trial
15–50%Estimated share of weight lost with these medicines that comes from lean tissue
2/3Share of lost weight regained in the year after stopping the medicine (semaglutide trial)
Why is muscle lost during weight loss?
When the body takes in less energy, it uses lean tissue, including muscle, as well as fat. In the 140 people whose body composition was measured in the large semaglutide trial, fat mass fell by 19.3% and lean tissue mass by 9.7% in those taking the medicine. Because more fat was lost, the proportion of lean tissue in the body rose; in other words, body composition improved overall.
Even so, part of the lean tissue lost is muscle. Muscle matters for strength, balance, blood sugar use and independence in later life. That is why protecting muscle matters even more in older age, in people whose muscle mass is already low and in those who are inactive.
What do the guidelines recommend?
- World Health Organization (2025): states that GLP-1 medicines may be used for the long-term treatment of obesity in adults, and that intensive behavioural support such as healthy eating and physical activity programmes may be offered alongside them. It stresses that the medicine alone is not enough and that long-term data are limited.
- US nutrition and obesity societies (2025): recommend strength exercise and enough protein to limit muscle and bone loss during weight loss; monitoring for deficiencies of iron, B vitamins, calcium and vitamin D; and managing gastrointestinal side effects.
- General recommendation: The World Health Organization recommends 150–300 minutes of moderate aerobic activity a week for adults, plus strength exercise for the major muscle groups on at least 2 days a week.
The benefit of exercise
In Denmark, 195 people who had lost an average of 13.1 kg on a low-calorie diet were assigned for a year to exercise, liraglutide, both, or placebo. Compared with placebo, the exercise group weighed 4.1 kg less, the liraglutide group 6.8 kg less and those doing both 9.5 kg less. Body fat percentage fell most, by 3.9 points, in those doing both; the only group that preserved lean tissue was the exercise group.
In a 6-month study of 160 frail adults over 65 with obesity, those who combined weight loss with both aerobic and strength exercise improved their physical function the most.
No completed study has yet tested how well strength exercise protects muscle while taking semaglutide or tirzepatide; a randomised trial of 232 people is under way. That trial aims for strength exercise at home 3 days a week and 1.6 grams of protein per kilogram of body weight a day.
In practice
- StrengthDo exercises that work the major muscle groups on at least 2–3 days a week. Do each set until the last few repetitions feel hard; increase the resistance as it gets easier.
- ProteinWhen your appetite is low, eat protein-rich foods first; add a protein source to every meal.
- GoKeep active every day with at least 150 minutes a week of brisk walking or a similar activity.
- Fluids and side effectsTell your team if you have nausea, constipation or diarrhoea; eating small amounts often can help.
- MonitoringTrack your strength as well as your weight; for example, repeat the 30-second chair test every few weeks.
Exercises at home
Six exercises to protect your muscles
The first five movements are strength exercises for the leg, hip, chest, back and calf muscles; the sixth supports daily activity. The numbers of repetitions are general suggestions; if you are just starting or have a health condition, plan your programme with your doctor or physiotherapist.
Wall press-up
Place your hands on a wall at chest height. Bend your elbows to bring your chest towards the wall and push back. When it gets easier, move to a kitchen worktop and then to the floor.
8–12 reps, 2–3 setsResistance band row
Fix the band to something sturdy. Keeping your elbows close to your body, pull the band towards you, squeeze your shoulder blades together and release slowly. Use a stronger band as you get stronger.
8–12 reps, 2–3 setsBridge
Lie on your back with your knees bent and feet on the floor. Squeeze your buttocks and lift your hips, hold briefly and lower slowly. When it gets easier, do it on one leg.
10–15 reps, 2–3 setsHeel raises
Hold on lightly to a worktop. Lift both heels together to rise onto your toes, then lower slowly. When it gets easier, do it on one foot.
12–15 repetitions, 2–3 setsBrisk walking
Walk at a pace where you can talk but are slightly out of breath. It is an easy way to stay active on days when you are not doing strength exercises.
At least 150 minutes a week; spread across the daysFor a weekly strength programme, see the home strength circuit; for more on muscle loss, see the sarcopenia guide.
Frequently asked questions
How much muscle will I lose on weight-loss medication?
It varies from person to person. In the body composition measurements of the large semaglutide trial, fat mass fell by 19.3% and lean (including muscle) tissue mass by 9.7%. Because more fat was lost, the proportion of lean tissue in the body actually rose. Researchers estimate that about 15–50% of the weight lost with these medicines comes from lean tissue.
Is muscle loss always bad?
Some loss of lean tissue is expected when losing weight. But strength and mobility matter, especially in older age and in people whose muscle mass is already low. In a study of 160 older adults with obesity, those who combined weight loss with aerobic and strength exercise improved their physical function the most.
How much protein should I eat?
US nutrition and obesity societies recommend getting enough protein alongside strength exercise to limit muscle loss. When your appetite is low, adding a protein source (eggs, yoghurt, cheese, pulses, meat, chicken or fish) to every meal helps. An ongoing study is aiming for 1.6 grams of protein per kilogram of body weight a day. If you have kidney disease, decide on your protein intake with your doctor.
Does exercise boost the effect of the medicine?
One study supports this. When 195 people who had lost an average of 13 kg on a low-calorie diet were followed for a year, those who kept the weight off best were those combining liraglutide with exercise: they weighed 9.5 kg less than with placebo, and their body fat percentage fell the most. The only group that preserved lean tissue was the exercise group.
What happens when I stop the medicine?
Some of the weight may come back. In a study following 327 people who stopped semaglutide after 68 weeks, about two thirds of the weight lost was regained within a year, and the improvements in cardiovascular health largely went back to where they started. That is why it matters to build strength exercise and eating habits while you are taking the medicine.
Has the benefit of strength exercise with these medicines been proven?
Not fully yet. According to the authors of a study protocol published in 2026, no completed study has tested the effect of strength exercise while taking semaglutide or tirzepatide; a study of 232 people is under way to answer this. Even so, it is well established that strength exercise protects muscle during diet-induced weight loss, and guidelines recommend strength exercise alongside these medicines.
Exercise advice for blood sugar is in the exercise and type 2 diabetes guide.
When should you see a doctor?
- Severe, persistent abdominal pain, pain spreading to the back, or vomiting: seek help straight away
- Vomiting or diarrhoea so bad you cannot keep fluids down, dizziness, or passing much less urine
- Marked weakness, or starting to struggle with stairs or getting up from a chair
- If you also take diabetes medicine, signs of low blood sugar such as shaking, sweating or a pounding heart
Sources
- World Health Organization. WHO issues global guideline on the use of GLP-1 medicines in treating obesity. 1 December 2025.
- Mozaffarian D, Agarwal M, Alexander L, et al. Nutritional priorities to support GLP-1 therapy for obesity: a joint Advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society. Am J Clin Nutr. 2025;122:344–367. Summary: Patient Care, 9 July 2025.
- Wilding JPH, et al. Body composition (DXA) substudy of the STEP 1 trial, conference abstract: Newswise.
- Wilding JPH, Batterham RL, Davies M, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: the STEP 1 trial extension. Diabetes Obes Metab. 2022;24(8):1553–1564.
- Lundgren JR, Janus C, Jensen SBK, et al. Healthy weight loss maintenance with exercise, liraglutide, or both combined. N Engl J Med. 2021;384(18):1719–1730. Summary: McMaster Optimal Aging Portal.
- D'Souza AC, Lau KJ, Phillips SM. Exercise in the maintenance of weight loss: health benefits beyond lost weight on the scale. Br J Sports Med. 2022;56(13):771.
- Villareal DT, Aguirre L, Gurney AB, et al. Aerobic or resistance exercise, or both, in dieting obese older adults. N Engl J Med. 2017;376(20):1943–1955. Summary: American Family Physician.
- Alawadhi AA, Alroudhan D, Alsaeed DJ, et al. LEAN mass Preservation with Resistance Exercise and Protein during semaglutide and tirzepatide therapy (LEAN-PREP study): a protocol for a randomised controlled trial. BMJ Open. 2026;16:e116911.
- Bull FC, Al-Ansari SS, Biddle S, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. Br J Sports Med. 2020;54(24):1451–1462.
- Patient Care. FDA approves orforglipron, first oral GLP-1 receptor agonist for weight loss with no food or water restrictions. 1 April 2026 (side effects and warnings for the drug class: pancreatitis, kidney injury from fluid loss, low blood sugar with insulin or sulfonylureas).