Episode #142: Your Body Composition Matters More Than Your Weight

In this episode of Conquer Your Weight, Dr. Sarah Stombaugh explains why focusing solely on the scale can be misleading—and why body composition is the real measure of health.

You’ll learn:

• The difference between body weight and body composition.
• Why muscle mass is crucial for metabolism, strength, and longevity.
• How fat distribution affects your health more than total weight.
• Practical ways to measure progress beyond the scale.
• How to celebrate non-scale victories and shift your mindset.

Whether you’re just starting your weight loss journey or frustrated by the number on the scale, this episode will help you see progress in a whole new way.

Listen now to discover why the scale is just one small piece of your health story—and how body composition can give you a clearer, more empowering picture of success.

Ready to get started on your weight loss journey? We're enrolling patients now at our Charlottesville, Virginia office and by telemedicine throughout the states of Illinois, Tennessee, and Virginia. Visit www.sarahstombaughmd.com to learn more and get started today. 

Are you taking a GLP medication? We are thrilled to share we are offering an online course, The GLP Guide, to answer the most common questions people have while taking GLP medications.

To sign up, please visit: www.sarahstombaughmd.com/glp

Transcript

Dr. Sarah Stombaugh:
This is Dr. Sarah Stombaugh, and you are listening to the Conquer Your Weight Podcast.

Announcer:
Welcome to the Conquer Your Weight Podcast, where you will learn to understand your mind and body so you can achieve long-term weight loss. Here's your host, obesity medicine physician and life coach, Dr. Sarah Stombaugh.

Dr. Sarah Stombaugh:
Hello, everyone, and welcome to this week's episode of the Conquer Your Weight podcast. We are talking about body composition today, and this is one of those topics that I realized looking back through old podcast episodes, oh my goodness, we have sort of alluded to this. I've had conversations about this on social media, but I have not had a specific episode dedicated to body composition, and this has been a huge conversation in especially in light of the popularization of many of the GLP medications like Ozempic, Wegovy, Zepbound, and Mounjaro. And what does it mean to lose weight versus lose fat mass? And so today we are going to talk about why body composition matters more than the scale. 

And my guess is you've had this experience in the past if you've been on a weight loss journey, particularly when you've been really involved in exercise, seeing that, oh my God, I'm stepping on the scale and the number is the exact same, but how could that be? Because you might be noticing other things like my clothes are feeling, you know, they're feeling looser. They're fitting a little bit differently. I'm feeling more energized. I'm feeling stronger. Why? Oh my goodness. Am I not seeing the scale budge? And that could be so, so frustrating when the scale is the single metric that we are looking at. And so in today's episode, we are going to talk about why body is a better measure of health compared to just weight alone. Now, we talked about this a bit in the episode two of metabolic adaptation. And so I think this episode will mirror that really nicely in some ways and talk a little bit more about the differences between weight and body composition. So it's really fascinating when patients come into my clinic, invariably people say, I want to lose weight. And when we say that, what we actually mean is I want to lose fat mass. Now, when I mirror that back to somebody, what they will say is, well, of course, I want to lose fat mass. And in order to preferentially lose fat mass in the weight loss journey, there are things that we have to very intentionally do, have to do in order to protect and support our current muscle mass, as well as ideally even build up muscle and support our health in that way. 

When we think about our total body composition, there is fat mass and there is lean mass. And our lean mass is made of things, including our muscles, but our bones, our organs, everything else basically is this other. And then we have other things like water that's in our body, of course, makes up a huge percentage, waste products that are in our body, like foods we've eaten that are in the process of being digested. But when we think about body composition, a lot of times we can think about our total mass, but then thinking about what is the ratio of our fat mass to our lean mass? And this can be so, so much more important. When we look at metabolic health outcomes, and so this is looking at things like cardiovascular disease, risk of heart attack, for example. This is looking at metabolic disease like risk of type 2 diabetes or prediabetes, insulin resistance, conditions where we're seeing visceral adiposity where we gain weight, particularly in and around our organs. And so people will have weight gain that's happening centrally in our body. Those things will often correspond with higher fat mass compared to muscle mass. So if someone steps on the scale and sees a number that doesn't necessarily tell us or doesn't tell us anything about what is their fat mass and what is their muscle mass. 

So what we do know is that many people are at risk for losing muscle as they lose weight. And that's because as we are losing weight, our body is going to be looking for the energy it needs in order to fuel all of the different systems of your body. When we think about general fuel for our body, we think about calories. So calories are just a unit of energy and saying, how much energy does it take for my body to function? And we can function on carbohydrates, we can function on protein, we can function on fat. Our body is able to burn each of those three different macronutrients for just soul energy purposes, but there are certain functions in our body that require certain macronutrients. So for example, there are certain functions that require fat or require protein. And what can really commonly happen during the weight loss journey is that there are functions that require protein. And if our body is not getting adequate protein through diet and daily nutrition, then our body may start to break down muscle for those amino acid needs, but certainly maybe even just for fuel needs. So muscles can be broken down just like our fat stores in order to fuel our body. And that is certainly something that we do not want. It can be helpful to know what your muscle mass looks like at the beginning of a journey, and then to track it alongside of your weight loss goals. 

Depending on where someone is starting out, sometimes our goals that they are maintaining their muscle or minimizing their muscle mass loss, depending on the rate at which they are losing weight or how much weight someone needs to lose. We may even be talking about trying to increase their lean muscle. Now it can be really challenging for the body to both lose weight and gain muscle at the exact same time. The body can be metabolically positive in a way that it's gaining, it's putting on weight, it's putting on muscle, and it can be metabolically breaking things down. And it's challenging for both of those things to happen in the same time, but we can sit sort of work through those two things and do things that even if we are in a metabolic deficit, our body is catabolic and breaking things down, that we are able to support and maintain our muscle mass as much as possible. And body composition matters so much in the context of, as I said, our metabolic health, but it also plays a role in things like our function and our longevity. So we think about what our strength is, what is our energy? How do we feel? Do we feel energized? day over day? Do we feel strong? Do we feel like we're able to do the activities that we want to do? As we think about, especially transitioning into our elderly years, are muscles going to be really important for protecting against frailty, reducing the risk of fall, reducing the risk of disability? So being able to walk independently, being able to rise from a seated position, or even get up off of the floor if we've had a fall. Muscle is really important for us to be able to function. And when we look at the correlation with our health metrics into many decades of life, into our 70s, 80s, 90s, and beyond, muscle mass is one of the things that correlates very strongly with longevity. So certainly in the weight loss journey, we want to make sure that we're doing everything to protect our muscle mass while ideally even building it up if we can. 

Now, fat distribution matters as well. And we've talked about the scale, so seeing what is the number on the scale, it's going to have limitations because we see fluctuations for all sorts of different reasons. So for one, let's say you're losing fat mass and you're gaining muscle mass, you're going to see the exact same number on the scale. And that can be super frustrating if you feel like you're relying on that feedback, which we often do. We want to see that number continuing to move in the direction of our goals. There can be other things that are limiting on the scale. like fluctuations in our water, digestion, if we've eaten, if we've exercised, if we've traveled, if we're about to start our period, other hormonal changes, all of these things can play a difference in the number that we see on the scale. And so what can happen and what we see sometimes in the clinic is patients who kind of on both ends of the spectrum, someone who is losing weight and they're losing muscle mass along with their fat, and they may feel kind of cramped. They feel run down, they feel weak, and they don't feel energized. And this can be really problematic because if we are really preferentially losing our muscle mass, the health outcomes are not there. Even if we are losing significant fat mass, if someone is losing a lot of muscle, they just might feel really run down and really depleted and feel like they can't, maybe they can't even exercise because they're like so exhausted that the idea of exercise is just simply too much. And so it can be this really challenging cycle. 

And I see this happen sometimes in the context of GLP medications where someone has been titrated up really quickly on their medications, maybe even beyond what, you know, they were responding well at lower doses yet continue to titrate up to higher and higher doses. And occasionally we encounter people who've been on pretty high doses of these GLP medications and they're like, I just don't feel like eating any anything and they feel miserable. We've even had situations when we're really carefully titrating someone. I'm thinking of one patient in particular that as we moved her from the 7.5 to the 10 milligram dose of Zepbound, I met with her for a visit and you could just see her energy levels. It was like, oh my gosh, are you sick? Are you not feeling well? And she just had that depleted look about her. And she felt during that month as she had moved up on dosing that, oh man, this is more than my body needs. I don't feel like I'm able to eat and fuel my body throughout the day. And so for her, the move was to scale back down on the dose to the 7.5 milligram and continue to support her in what felt like a slow weight loss. And I'll even put sort of air quotes on that, but a weight loss by which she was able to exercise regularly. She was walking, she was weight training, she was able to eat consistently throughout the day, make choices that were in line with her goals and really fuel her body. And we were still seeing that number sort of nudging down, but not in a way that, oh my gosh, I've pushed myself to the point where I can't eat anything. And now I'm just finding myself really depleted. And so when we're doing that, sometimes things go too quickly. And so someone's losing both muscle mass as well as fat mass. 

But the other thing happens as well that I mentioned at the very beginning, and this is a positive thing where someone is maintaining weight, maybe even gaining a little bit of weight. But if you looked at body composition, we'd see that there is a shift downward in body fat mass, a shift upward in muscle mass. So even though the number on the scale is the same, this person looks leaner, their clothes are fitting better, they're feeling stronger. If we did their lab results, we may see improvements in labs across especially some of those metabolic things like blood sugar or A1C or cholesterol or liver enzymes or blood pressures, for example. So we see these changes that things are improving despite the fact that the number on the scale looks the same. And so how do we assess this and pay attention to body composition versus just weight on the scale? Now, there's a lot of different ways by which we can assess body composition. There can be everything from imaging modalities like doing whole body MRI or DEXA scans. DEXA scans, interestingly, are the gold standard, but I'm aware of some longevity clinics that actually use whole body MRI, which is kind of wild in order to look at body composition. But these are able to look at all of the different components of total body mass and break it down into fat mass, lean mass, including bone mass and muscle mass. We can look at things like a bioimpedance scale. So this is probably the most commonly used technology and it's become really popularized over the last couple of years, especially things like in-body machines. There are certain second equipment, other brands as well that do it, but it's basically using an electrical current that gets sent throughout your body in order to see how does that electrical current move through different types of tissues. And we know that that transmits differently through fat mass versus muscle mass versus bone mass, for example. These do have some limitations in that depending on the time of day, depending on your hydration status, your exercise status, those can play a really significant factor in seeing fluctuations. And so it is best if you can do any sort of bioimpedance in body or otherwise at a very similar time per day, ideally in the morning time with similar hydration status, probably pre-workout. And so we know that doing exercise, being dehydrated, losing the electrolytes alongside of that may play a difference too in those readings. And so it can be a little frustrating if you're trying to compare one reading to another reading, but these can track really nicely over time, looking at overall general trend Although there is that, like I said, wiggle room for error. 

Older technologies like skin fold calipers, certainly there's probably some people that still do these. I'm not aware of any physicians that are still using these in their practice, but a skin fold caliper can actually be a pretty accurate assessment. It does need to be done by someone who is trained in it. We do see a lot of variants when you look at from one person measuring it to another person. So you would want to make sure that there's consistency in terms of who is doing the measurements. Are they someone who is trained and experienced in this area? But looking at skin folds across the arm, across the abdomen, into the thighs, for example, we can get some good estimates of body composition, again, for someone who's trained and experienced in that. A really good at-home tool is something like waist circumference or other body circumference metrics. We know that per volume, muscle mass and fat loss, even though they weigh the same, the volume of those is very different. And so if you think of the volume of muscle mass, let's say five pounds of muscle is going to be this tight little brick of muscle compared to five pounds of fat tissue was going to be larger, kind of soft and globular. And if you put those two things on a scale and weighed, this is muscle mass, and this is fat mass, they'll balance one another out. But you'll see that the muscle mass takes a much larger or much smaller volume, rather a much smaller amount of size. And so this is where we see the someone who does have more muscle mass or someone who is gaining muscle and losing fat may see those things like clothing changes and smaller waist circumference, for example, even though the number and the scale may not be moving a whole lot. So waist circumference or other body circumference areas are a phenomenal tool. This is one we very, very commonly use in our clinic in combination also with bioelectrical impedance. 

But these can be great ways to track over time and look at, am I improving, not just seeing a decrease on the number of scale, but am I actually improving my health and improving my longevity? I think one of the things that we've seen come up so much when this conversation has been happening in the media and in social media is that concern for the person for whom they've lost weight. Maybe their appetite's been overly suppressed to the point where they feel like they're not able to eat much during that journey. And we really do see start to see that person lose both fat mass and really also losing muscle mass in a significant way. And it doesn't improve their health in the most ideal way. It doesn't necessarily improve their health at all depending on what those ratios look like for the individual. I think one of the other bigger challenges is that it's pretty early in life, usually in our 30s even, that we start seeing some decreases in muscle mass. And so if left unchecked, if we just keep up our regular same activity day over day, week over week, month over month, as we enter into our 30s, we start seeing early decline in our muscle mass. We'll see that through our 30s, 40s, and 50s, sometimes losing three to 5% of our total muscle mass in a year. And then we'll see that it accelerates in our elderly years into our 60s, 70s, and 80s and beyond. There are people for whom averaging losing five to 8% total muscle mass year over year. And so there is this natural decline in muscle mass that happens as we get older and so being mindful of that especially in the weight loss journey we want to make sure that we are really counseling our patients about this making sure that they are aware of the risk of losing muscle mass such that we don't actually decrease the risk of falls or osteoporosis or you know needing to rely on a cane or a walker or a wheelchair when they've never had to rely on devices before to ambulate And so that does not improve somebody's health. 

And I think that's where a lot of pushback for these medications has come up in, are we doing more harm than good? And are there cases of that? Certainly. Is that preventable with monitoring closely, with making sure that you're looking at how your individual body is responding, making sure that you're taking measures to address your muscle and address your strength? We can absolutely do that. And so as we think about that, A lot of times when we look at what is our muscle mass versus fat mass, I encourage people to step away from the scale, setting goals beyond just the number on the scale with how often am I exercising? How strong do I feel? What is my endurance? What is my clothing fitting like? How am I noticing differences there? Other non-scale victories like sleeping, like energy, like seeing improvements in our metabolic health. Like I mentioned, some of those lab changes like blood sugar, cholesterol, maybe seeing changes in liver enzymes or blood pressure numbers. So seeing some of those, paying attention to what does our life activities look like? Are we able to celebrate things like fitting into an airplane seat or a movie theater seat, getting back to an activity like biking or horseback riding or something else that we've really enjoyed in the past? Are there other non-scale victories that indicate overall total health outcomes but as well as paying attention to the things like our muscle mass, which plays a role into that energy and sleep place. And so reframing our success in a way that we're not just chasing a smaller number, that we're working on building a stronger and healthier body. And I know that this is often easier said than done in that our society often is looking at that number on the scale and really able to track that. We see our weight, we see our BMI. That is how so often in the doctor's office, we are tracking things, but there are other metrics of success as well. And practicing paying attention to those, celebrating those is really important. So the scale is just one tool, certainly an important tool, but it's just one tool in the toolbox. Our body composition is going to tell us the real story, paying attention to how is our body changing over time in terms of decreasing body fat mass, stabilizing, or even improving our muscle mass, paying attention to those metrics like energy, like endurance, like strength, for example. So I want to encourage you to shift your focus from just the number and the scale to what is your overall health and fitness. The next time you get discouraged by the number you're seeing on the scale, ask yourself some of those questions. Am I feeling stronger? Am I feeling healthier? Am I clothes fitting differently? Am I feeling more energized? Are there other things that are happening in your life? Paying attention to those will help keep you on track so that you're seeing both those non-scale victim as well as those scale shifts as well. 

If you're looking for a doctor to support you in this comprehensive way, I am enrolling patients for in-person visits in Charlottesville, Virginia and for telemedicine throughout the states of Illinois, Tennessee and Virginia. Thank you so much for joining us for today's episode. We'll see you all next time. Bye-bye.