Muscle & Body Composition
If you're considering semaglutide or tirzepatide for weight loss here in Chattanooga, you've probably read the headline numbers — 15%, 20% of body weight gone. What the marketing almost never tells you is what kind of weight you lose. Because not all of it is fat. Some of it is muscle. And the difference between those two outcomes is the difference between getting lighter and getting healthier.
This is the cutting edge of obesity medicine right now, and it's the question I think about with every patient. Let me walk you through it the way I'd explain it across the desk.
Why GLP-1 weight loss isn't all fat
When you lose weight rapidly — by any method, including a GLP-1 medication — your body draws on more than fat stores. It also draws on lean tissue, which includes skeletal muscle. This isn't unique to these drugs; it happens with any large calorie deficit, including old-fashioned crash dieting. But because GLP-1 medications are so effective at reducing appetite, the deficit can be large, and the lean-mass question becomes real.
How much? In the major obesity trials, a meaningful share of the weight lost on a GLP-1 came from lean mass rather than fat. In the published body-composition data on semaglutide, roughly a quarter to a third of total weight lost was lean tissue. That is real, and it's worth taking seriously — but read the next sentence carefully: it is manageable, not catastrophic, when someone is actually paying attention to it.
Here's why muscle matters beyond how you look. Muscle is metabolically active tissue — it's a major site where your body burns glucose. It's tied to strength, balance, and independence as you age. And, critically, it helps protect against weight regain: lose muscle now, and you can come out the other side with a slower metabolism that makes the weight easier to put back on. For a program built — like ours — around getting you to your goal and keeping you there, protecting muscle isn't a nice-to-have. It's central.
What's coming: the muscle-preservation frontier
This is where obesity medicine is moving fast, and it's genuinely exciting. Researchers have recognized the muscle question, and an entire class of investigational drugs is being developed specifically to fix it. I follow this literature closely so my patients aren't getting last year's playbook.
The most striking example is an investigational antibody called bimagrumab, which blocks the signals that normally put a brake on muscle growth. In a 2026 Phase 2b trial (BELIEVE, published in Nature Medicine, 507 participants), combining bimagrumab with semaglutide produced something no GLP-1 achieves alone: the weight that came off was overwhelmingly fat, with lean mass largely protected.
A second frontier is the amylin class — drugs like cagrilintide that mimic a natural hormone your pancreas already makes. Early trials suggest meaningful weight loss (roughly 10–12% as a single agent in trials) with a different side-effect profile than GLP-1s, and researchers are actively studying how these agents affect body composition. The science here is moving month to month.
Bimagrumab and cagrilintide are investigational. They are not FDA-approved, and Summit cannot prescribe them — and you should be skeptical of anyone who implies otherwise. I mention them because they confirm what the research community now agrees on: protecting muscle during weight loss is a real clinical goal, not a marketing line. The encouraging news is that you don't have to wait for these drugs to act on it.
What Summit actually does about muscle — today
Here's the part that matters for you right now. You don't need an experimental drug to protect your muscle during weight loss. You need a physician who is watching for it and a protocol built around it. That's what we do at Summit Metabolic Health, and it's a large part of what "physician-led" actually means day to day.
1. We dose deliberately, not by a package-insert calendar
Faster isn't better. When weight comes off too fast, more of it tends to come from lean tissue. I titrate to your tolerance and your goals — finding the dose that produces steady, sustainable fat loss rather than the largest possible number on the scale this month. As an ER physician by training, I watch your whole physiology, not just your weight.
2. We make protein a non-negotiable
Adequate protein intake is one of the best-established tools for protecting lean mass during a calorie deficit. The problem on a GLP-1 is that your appetite drops — so you have to be intentional, because it's easy to under-eat protein when you're simply not hungry. We give you a real target and check in on it.
3. We prescribe resistance training as part of the plan
Resistance training is the strongest signal you can send your body to keep the muscle it has while you lose fat. It doesn't have to mean a gym five days a week. It means a structured, progressive plan that fits your life — and a physician who treats it as part of the prescription, not an afterthought.
4. We build in an exit strategy
Summit is the only GLP-1 program designed to end. Protecting muscle on the way down is exactly what makes a durable result possible — because the body composition you arrive at goal with is the body composition that determines whether the weight stays off. When you reach your goal, we wean you off the medication in a controlled, physician-directed process, with your muscle preserved to carry the result forward.
The Chattanooga difference: a physician who reads every chart
Most online GLP-1 programs are built to scale: more patients, less physician time, a questionnaire and a prescription. The muscle question is precisely the kind of thing that falls through the cracks of that model — because catching it requires someone who actually knows your case.
At Summit, I personally review every chart. Every patient gets a monthly video visit with me — not a coach, not a nurse queue — and direct access between visits. We serve patients across Tennessee, Florida, Washington, Ohio, and Georgia, in person here in Chattanooga and via telehealth. And our program gets cheaper as you get healthier, because it's designed to get you to a finish line, not to bill you forever.
If you've been doing everything right and still struggling — or if you've lost weight before and watched it come back — the muscle question may be part of the story no one ever told you. Let's talk about it.
Curious whether a physician-led GLP-1 plan built to protect your muscle is right for you? Dr. Miranda personally reviews every application.
Book a Free ConsultationThis article is educational and is not medical advice, a diagnosis, or a treatment recommendation for any individual. GLP-1 and investigational medications carry risks and are appropriate only for certain patients after evaluation. Trial figures cited (BELIEVE, Nature Medicine 2026; semaglutide body-composition data; cagrilintide Phase 2/3) are group averages — individual results vary. Bimagrumab and cagrilintide are investigational and not FDA-approved. Summit Metabolic Health · 200 W Martin Luther King Blvd, Ste 1000, Chattanooga, TN 37402 · (423) 407-7748 · summitmetabolichealth.com · Serving TN, FL, WA, OH, GA.
