For people on a GLP-1
Keep your muscle while you're on a GLP-1
About a quarter of the weight lost on GLP-1 medications is lean mass. Lifting two to four times a week and eating enough protein is how you make the rest of it fat. Your prescriber handles the medication; Kris coaches the lifting and the food.
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By Kris Oddo, NASM-CPT · Updated
Do GLP-1 medications take muscle as well as fat?
Some, yes. A review of 22 trials and 2,258 people found that lean mass made up about 25% of the weight lost on GLP-1 medications. The other 75% was fat, which is why the scale alone cannot tell you how it is going.
The same review found that lean mass as a share of the body did not get worse, so the medication is not singling out muscle. It is producing a lot of weight loss, and a quarter of a large number is still a real amount of tissue.
That quarter is the part you can influence. Lifting tells the body which tissue to keep, and protein gives it the material to keep it with.
What did the tirzepatide body scans show?
In the SURMOUNT-1 body-scan substudy, 160 people had full scans before and after 72 weeks. Those on tirzepatide lost 21.3% of their bodyweight, 33.9% of their fat and 10.9% of their lean mass.
Of everything they lost, about 75% was fat and 25% lean mass, the same split as the placebo group, who lost far less. Most of the people scanned (73%) were women.
Lean mass on a scan also counts water and organs, not only muscle, so it is a rough measure. Strength is the better day-to-day signal: if your lifts hold while the weight comes down, you are keeping what matters.
Source: Look et al., 2025, Diabetes, Obesity and Metabolism (PMID 39996356)
Does lifting actually help while you are on a GLP-1?
It is the best tool available, and the trials testing it directly are still running. A 2024 review in Diabetes Care put lean-mass loss on these medications at about 10%, or 6 kg, and found supervised lifting for over 10 weeks adds about 3 kg of lean mass.
The review also found strength gains of about 25% from that training, in men and women, and its authors recommend tailored resistance training alongside these medications.
A trial of protein plus lifting during semaglutide and tirzepatide treatment (LEAN-PREP) has published its plan but not its results. Until it does, nobody can promise you an exact number. Lifting is still the safe bet, because the downside is small and the upside is your strength.
Source: Locatelli et al., 2024, Diabetes Care (PMID 38687506)
How do you eat enough protein when you are not hungry?
Make protein the first thing on the plate, every time. Muscle gains from lifting top out at about 1.6 g of protein per kg of bodyweight a day, according to a review of 49 trials and 1,863 people, so that is the number to work toward.
With a smaller appetite, the trick is order, not volume: eat the protein first, use foods that go down easily (Greek yogurt, eggs, fish, a shake), and spread it over three or four smaller meals.
If you cannot get close to the target for more than a week or two, or eating at all is hard, tell your prescriber. Low intake on these medications is a medical conversation, not a willpower problem.
Source: Morton et al., 2018, British Journal of Sports Medicine (PMID 28698222)
What does a coach do, and what stays with your prescriber?
Your prescriber owns the medication. A coach owns the training and the food around it. A 2025 joint advisory from four obesity and nutrition societies lists muscle and bone loss as a main problem on GLP-1s, and resistance training and diet as the way to protect them.
The same advisory notes these medications cut weight by 5% to 18% in trials, and that many people stop taking them and regain weight. Muscle and habits you build now are what you keep if that happens.
So Kris will never tell you what dose to take, whether to start, or whether to stop. He will build your lifting around your energy, set your protein around your appetite, and adjust both every week.
Source: Mozaffarian et al., 2025, Obesity, joint advisory of four societies (PMID 40445127)
How do you know you are keeping your muscle?
Track your lifts, not just the scale. Across 25 trials of people dieting to lose weight, adding resistance training barely changed scale weight (0.32 kg) but protected fat-free mass and increased fat loss.
Two people can lose the same weight with very different results in the mirror. The scale cannot see the difference; your lifts and a tape measure can.
Coaching tracks three things each week: strength on a few repeatable lifts, how many days you hit your protein, and your waist. If strength holds while the weight drops, the plan is working.
Source: Binmahfoz et al., 2025, BMJ Open Sport & Exercise Medicine (PMID 40909191)
A few more questions
Will Kris tell me what dose to take?
No. Dosing, side effects, and whether to start or stop belong with your prescriber. Coaching covers lifting, protein and your weekly routine.
I have never lifted. Can I still start?
Yes. The plan starts with a few basic movements at a weight you can control, two or three times a week, and builds from there as your energy allows.
Is this only for men?
No. Kris coaches men and women. Most people in the tirzepatide body-scan study above were women, and the lifting and protein advice applies to both.
