Medications like semaglutide and tirzepatide are very good at one thing: turning down your appetite so the weight comes off. My job is the other half — making sure what you lose is fat and not muscle, and that the results stay with you. Here is how we do that together.
Why we keep an eye on muscle
When weight comes off quickly, some of it can come from muscle, not just fat. That matters: losing muscle is how people end up lighter but weaker — with less energy, weaker legs, and a higher chance of slips and falls down the road.
The good news is that this is very preventable. Your body keeps the muscle it is given a reason to keep. A little strength work and enough protein are that reason — they tell your body, "hold on to this part." So while the medication handles your appetite, we make sure the weight you lose is the right kind.
A way to picture it: think of the medication as a strong tailwind pushing your boat along. It is doing real work — but someone still has to steer, or you drift off course. The strength work and protein are the steering: they keep you headed toward "lighter and stronger," not "lighter but weaker."
Both roads lose weight. Let it just shed, and muscle goes with it — lighter but weaker. With strength work and protein, the fat shrinks and the muscle stays.
What helps
Protein first, every meal. Because the medication makes you less hungry, it is easy to eat too little — especially protein, which is exactly what protects your muscle. Put protein on the plate first: eggs, yogurt, fish, chicken, beans, tofu. Your care team can give you a target.
Two or three short strength sessions a week. This is the big one. Working your major muscles — legs, back, chest, arms — is the signal that tells your body to keep its muscle while the fat comes off. It does not need to be long; it needs to be regular.
Keep moving most days. Walking, stairs, errands, the activities you enjoy — all of it helps your heart and your results. Strength work is the priority, but everyday movement adds up.
Drink enough, and don't skip meals entirely. Less appetite can quietly leave you under-fueled and a little dehydrated. Sip water through the day and eat something, even small, before you exercise.
Build it to last. The habits you create now are what keep the weight off — even if the medication changes or stops one day. Start small enough that it fits your week.
Things you may notice, and what they mean
I'm barely hungry — is it okay to eat so little?
Eating less is how the medication works, and that's fine for total food. But your muscles still need protein and your body still needs fuel and water. Aim for protein at each meal even when your appetite is low — small and regular beats skipping.
Now that I'm on this, do I still need to exercise?
More than ever, honestly. The medication decides how much you lose; the strength work decides what you lose. Skip it and more of the loss comes from muscle. A couple of sessions a week is what keeps you strong.
Some days I feel queasy or wiped out when I try to exercise.
Common, especially early on or after a dose increase. It usually means you're a little under-fueled or low on fluids — not that exercise is bad for you. Eat a little, drink water, and we'll keep those days lighter. Tell me and we'll adjust.
You never have to push through feeling sick or dizzy. Easing off on a rough day is the smart move, not a setback.
The weight is coming off fast — that's good, isn't it?
It can be — as long as it's fat and not muscle. That's exactly why we strength-train and watch your protein. The scale can't tell the difference, but how strong and steady you feel can.
What happens if I stop the medication?
Weight often comes back when these medications stop — in the STEP 1 trial extension, people regained about two-thirds of what they had lost within a year of stopping — which is why we build real habits now rather than relying on the drug alone. The strength and routines you create are yours to keep, and they're what hold the line if things change.
When to stop and reach out
Most of what you'll feel — less appetite, some early queasiness — settles as your body adjusts. A few things are different and worth a call to your doctor or care team. Reach out if you notice:
Severe or lasting belly pain, especially with vomiting that won't stop — this needs prompt medical attention.
Vomiting so much you can't keep fluids down, or signs of dehydration (very little urine, deep fatigue, dizziness on standing).
Shakiness, sweating, or confusion — possible low blood sugar, especially if you also take insulin or other diabetes medication. Have a quick sugar source and let your team know.
Feeling noticeably weaker or struggling with stairs and standing more than the weight loss alone would explain.
When in doubt, ask. We would always rather hear from you.
You've got a powerful tool on your side — and a simple, doable plan to make the most of it: enough protein, a little strength work, and steady movement. That's how the weight you lose becomes strength you keep. We'll go at your pace, together.
Selected references
Wilding JPH, et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med. 2021. PMID 33567185.
Jastreboff AM, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). N Engl J Med. 2022. PMID 35658024.
Wilding JPH, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: the STEP 1 trial extension. Diabetes Obes Metab. 2022. PMID 35441470.
Cava E, Yeat NC, Mittendorfer B. Preserving healthy muscle during weight loss. Adv Nutr. 2017. PMID 28507015.