Naples Concierge Health
Dr. Danielle Grossman-Stuart, MD, board-certified in family medicine, Naples Concierge Health
Part one of a series on GLP-1s: exploring the current evidence on how to use them well.
If you’ve been considering a GLP-1 medication like Ozempic, Wegovy, Mounjaro, or Zepbound, you’ve probably focused on one number: what the scale says. That number matters, but it doesn’t tell you everything. On these medications, we need to pay attention to both the amount of weight you lose and the type of weight you lose.
Why the type of weight matters
Losing weight always means losing a mix of fat and muscle. This is true whether you lose weight through diet, surgery, or medication. Unless you take deliberate steps to protect it, a meaningful portion of what you lose is muscle.
Muscle is not just about how you look. Muscle is where your body handles blood sugar, which means it’s central to preventing diabetes. It’s what holds your skeleton up and protects you from injury. It’s a major driver of your metabolism at every age. In the long run, muscle is one of the best predictors we have of staying strong, mobile, and independent later in life.
My patients on these medications range in age from their early twenties to their eighties, and the same principles apply across the board. For a thirty-five-year-old, protecting muscle now means better metabolic health today and a stronger foundation to build on for the next four decades. For someone in their seventies, muscle is the difference between climbing your stairs at eighty and not.
Whatever brought you to these medications, muscle is not what you meant to lose.
What the research actually shows
In clinical trials of semaglutide (Ozempic, Wegovy), as much as 45 percent of the weight patients lost was lean tissue, primarily muscle. In clinical trials of tirzepatide (Mounjaro, Zepbound), that share was closer to 25 percent. Across studies, the range is wide.
Where you land in that range depends on your age, how much muscle you started with, how much protein you’re eating, and whether you’re doing strength training. In other words, these outcomes are not something the medication decides for you. They are shaped by what you do before and during treatment.
Muscle loss is not inevitable. Some people come through these treatments stronger than they started.
Why I’m cautious
Before joining Naples Concierge Health, I spent years caring for hospitalized patients, including some who came in with serious side effects from these medications. I want to be honest that this experience shaped my perspective with worst case scenarios but it made me want the safest, most effective version of this treatment for anyone I care for.
That starts with knowing what is actually happening in your body while the weight is coming off. And the scale cannot tell you that.
What to measure, and why
If you are considering or already taking one of these medications, body composition is worth measuring before you start and at regular intervals throughout treatment. This means going beyond the scale to understand how much of your weight is fat, muscle, and bone.
In the office, we can do body measurements and grip strength testing. Grip strength is a surprisingly reliable window into your overall muscle health. Outside the office, more detailed testing can measure your metabolism, cardiovascular fitness, strength, and balance. In Naples, I refer patients to LiveWell Health for this kind of comprehensive assessment when it’s helpful.
Tracking your protein intake is also worth the effort, at least for a few weeks. It’s real work, but a short period of tracking makes estimating far more accurate going forward.
Lab monitoring matters too
The scale and body composition tell you what’s happening structurally. Lab work tells you what’s happening biochemically. On these medications, thoughtful monitoring includes baseline and periodic checks of kidney and liver function, blood glucose control, thyroid history and function, and vitamin and mineral levels that can shift when appetite is significantly reduced. This isn’t about ordering every test possible. It’s about knowing your starting point, watching what changes, and adjusting when we need to.
These are not complications to expect. They are simply things worth watching, the same way we would with any medical treatment.
How much protein?
Current clinical guidance for preserving muscle on these medications is 1.2 to 1.6 grams of protein per kilogram of body weight per day. This is a range, not a single target, and the right number for you depends on your age, muscle mass, and whether you are strength training. For a 150-pound person, that works out to roughly 80 to 110 grams per day. For reference, a four-ounce fillet of salmon has about 25 grams of protein.
Reaching that target takes intention, especially on a medication that suppresses your appetite. Eating this way is its own challenge, and it deserves more than a paragraph. I’ll come back to it in a future article in this series.
What strength training does
Of all the things you can do to protect your muscle during weight loss, strength training is the most reliable. As someone who practices yoga and also strength trains, I would not give up either. But for protecting muscle specifically, lifting is the most important thing you can do. It does not have to be heavy or fancy, but it does have to be consistent. Two short sessions a week is enough to matter. The goal is to form a habit that you’ll actually keep, not a program you’ll abandon in a month.
How I approach this in the office
If you are working with me on a GLP-1 medication, you will not be left alone with a prescription and a scale.
Before you start, we establish what your body is made of and check specific blood tests. Throughout treatment, we track whether you are losing the right tissue and adjust your protein, training, and lab monitoring if we need to. You leave each visit understanding not just the number on the scale, but what is behind it.
The medication is only part of the plan. The rest is knowing what is happening inside your body and having the support to steer it in the right direction.
What to Do Next
If you are on a GLP-1 medication now, or considering starting one, ask about baseline body composition testing before you begin.
If you have already started and have not had your muscle mass checked, it is not too late. Ask at your next visit.
If you are working on your protein intake or strength training and want a plan built around your specific numbers we can create one together.
Reply to this email, use the portal, or call the office, and we’ll get you on the schedule.
If this was forwarded to you and you are on one of these medications without this kind of monitoring, we are happy to talk. We will help you figure out the right next step, whether that turns out to be us or not.
References: Neeland IJ, Linge J, Birkenfeld AL. Changes in lean body mass with glucagon-like peptide-1-based therapies and mitigation strategies. Diabetes, Obesity and Metabolism, 2024;26(Suppl 4):16-27.
Look M, et al. Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study. Diabetes, Obesity and Metabolism, 2025.
Mozaffarian D, et al. Nutritional priorities to support GLP-1 therapy for obesity: A joint advisory from the American College of Lifestyle Medicine, American Society for Nutrition, Obesity Medicine Association, and The Obesity Society. Obesity, 2025.