Muscle can turn into fat: Fact or Fiction?

Man running
More episodes in the Health Hullabaloo Podcast

Do muscle cells turn into fat when you don't exercise? Or can fat cells be transformed into muscle? Find out with Mark Faries, PhD, College of Medicine adjunct assistant professor and associate professor and state extension health specialist at Texas A&M AgriLife Extension.

Episode Transcript

Mark Faries: My name is Dr. Mark Faries, I’m here with Tim Schnettler. We’ve got a good question today, as we discussed, a very common question, this idea that we can turn fat into muscle. Or vice-versa, that we can turn muscle into fat. I’ve heard this a ton, especially all my years in the fitness industry, and that’s why people come, it’s like holidays came, I took a a break from exercising, and during that holiday or that break, I had all this muscle and it just turned into fat, and then, I need to get back and exercise and start eating better, so I can take all that fat and convert it back to muscle.

Tim Schnettler: Right.

Mark Faries: And we kinda talked last time about this idea of “thinny” or “skinny” fat

Tim Schnettler: Mm-hmm.

Mark Faries: and how people use terms like “soft” or “jiggly”, or, I don’t know why it is.

Tim Schnettler: Big-boned.

Mark Faries: Big-boned. And why do we think that it was muscle that turned into fat, I don’t really know that. But as we kinda dissect this out in particular, we’ll find that first and foremost, that a muscle cell, or myocyte is a completely different type of cell with a completely different purpose than a fat cell, or an adipocyte. So I think it’s easy to just consider it as apple and orange, they’re just two different things. But what’s interesting is a muscle cell, a muscle can store fat in it as well in the form of a triglyceride, so that we can break that down and the muscle can use that for energy. The liver can store fat as well, and we have the risk for fatty liver disease because of that fact. And so you have a fat cell that’s storing fat, and now you have a muscle cell, so maybe that’s where some of the confusion came from. But if we look at the function of both, I think it’ll kind of help clarify. So let’s start with the muscle cell, or the myocyte. The main function as we probably would think is a bunch of muscle cells combined we can then contract those and move our skeleton around. So that’s the main purpose. It’s packed in with muscle proteins, and if we go exercise or lift weights in particular,

Tim Schnettler: Right.

Mark Faries: And we haven’t in a while. We’re gonna create damage to that muscle cell. Those contractile proteins inside of there are gonna break apart a little bit. We get sore, and that kind of tender, that inflammatory response after workout,

Tim Schnettler: Right.

Mark Faries: When it’s hard to sit on the toilet or whatever.

Tim Schnettler: (laughs)

Mark Faries: That soreness is the recovery process occurring in that muscle because of that muscle damage from the workout. Now it’s not necessarily a scary thing, because we like the adaptations. Now we play it safe, but if we do everything right, we’re probably still gonna be fatigued and sore.

Tim Schnettler: Well and you hear trainers all the time saying “That’s a good thing,” you know, that soreness after you work out, they say it’s a good thing.

Mark Faries: It is, and its within reason. I mean, it gets so bad, and we’ve probably all been there to some point, where I worked my back so hard I couldn’t put my hands on the steering wheel or something like that.

Tim Schnettler: (laughs)

Mark Faries: But within reason, you’re right. And the reason they say it’s good is because when we create that damage, the brain does not like that, the body does not like this damage. So what it’s gonna try to do is repair itself, to the point that if you do that same workout, lift that same weight, do everything the same, then you’re not gonna create as much damage.

Tim Schnettler: Mm-hmm.

Mark Faries: We like that, because why? That repair process is going to make us stronger. So if I do bicep curls, for example, and I do three sets of maybe 10 repetitions with 20 pounds, so I would do those 10 reps and those three sets, so 30 total repetitions, I might be sore tomorrow.

Tim Schnettler: Mm-hmm.

Mark Faries: Well, that damage created, I go and fix that, the next time I try to do 20 pounds, three sets, 10 reps, I don’t create as much damage.

Tim Schnettler: Right.

Mark Faries: Because I’ve gotten stronger. And so when people wanna get strength, that’s an adaptation that comes from this damage. Well, one of the other adaptations that’s important for us today in this question, is the idea of the muscle cell getting bigger, and that’s called hypertrophy. And the reason that is, is, it’s sort of like, and as I look over here I see a picture of Mario Brothers, with bricks that you say.

Tim Schnettler: (laughs)

Mark Faries: And so when you smash those bricks with Mario if anybody knows what that is on this podcast, the idea is if those break down, we’re gonna have to repair that somehow. Well that’s how the muscle cells, you break them down, you’re gonna re-brick that house, you’re gonna re-brick that muscle, that’s why good nutrition, protein comes in, when we rebuild that muscle, so to speak, we pack in a little bit more protein in that muscle cell than we had previously. So that causes it to get a little bit bigger. If we’re smart in the way that we work out, we can work out in a particular way that makes the muscle even bigger and faster. So that’s why we have exercise prescriptions for strength, we have exercise prescriptions for endurance, for muscle hypertrophy, for example a common recommendation is you pick a muscle, let’s use our bicep again as an example, you would do somewhere around nine sets for that muscle, in one workout, somewhere between six and 12 repetitions. So what does that look like? I go to the gym, and I’m working biceps, I wanna get them a little bit bigger, so I get a barbell and I do 10 repetitions, and I do three sets of them, okay? And then I go to the dumbbells and I do three sets of 10 of dumbbells.

Tim Schnettler: Right.

Mark Faries: So now I’m at six sets. Then I go find the machine, the bicep curl machine,

Tim Schnettler: The bicep curl, right.

Mark Faries: and I do three sets of that, in one workout. So in my hour, or whatever it was, I did nine total sets on my bicep. That’s where again, commonly you’ll hear recommendations getting you into the muscle hypertrophy volume or range that is gonna give us that effect. I know people who do upwards of 20 sets per muscle group, per workout. Now these are the guys and gals that are in the bodybuilding business, and are trying to create a lot of damage. Many of these folks are also taking extra stuff to help them recover faster.

Tim Schnettler: (laughs)

Mark Faries: And to get a little bit bigger, a little bit more so than what most people can, so this idea though, is that you typically don’t stumble upon these workouts that produce large amounts of muscle hypertrophy. And by the way, we’ll probably talk about this later, but there should be no fear of getting big muscle, because again, you’re not gonna stumble upon this workout.

Tim Schnettler: Yeah.

Mark Faries: So the goal then is to get a very specific exercise and get the muscle to grow and get the muscle hypertrophy because we packed in that protein. Alright, so that’s muscle hypertrophy. It can happen, but this is how we need to work out. The opposite of that is if I sit around, and I don’t exercise as much as I did. There’s really no reason for the body to keep that extra protein. And they say, “If you don’t use it, you lose it.”

Tim Schnettler: You lose it.

Mark Faries: And that’s the way this is. You end up losing that, and if you’ve ever gotten a cast, on a broken arm, or knee surgery, or you’ve had to lay up in bed for a while, you notice that your muscles go get smaller, and that’s called atrophy. So we got hypertrophy is bigger muscle, and they technically say it’s the cross-sectional area that gets larger, that would be hypertrophy. And if the cross-sectional area gets smaller, that would be atrophy. So that does happen. But you notice the muscle’s not transitioning into anything at this point. It’s largely just getting bigger or it’s getting smaller, depending on the stimulus that we put on it. If we put the correct stimulus, we can maximize the hypertrophy. If we remove the stimulus for an extended period of time, then we will lose, we will atrophy. So that’s largely the muscle. The fat cells goal is to store fat. And so we are designed as humans to store as much fat as possible. The thought is that in times where food was scarce, if we had to go live in the woods out here, and we were trying to find food, the caloric intake would not be high, we largely don’t find a lot of fat in nature. If we did berries, and plants, eat a lot of plants, maybe a little wheat and if you could get an animal, it was probably a lean animal,

Tim Schnettler: Yeah.

Mark Faries: And not the ones we go buy at the store, and so the body’s ability when it did get fat to store that away was awesome. Because it increased probability of survival. And we had that energy. And it’s hard to convince the body to give that up. ‘Cause if I store it, I wanna keep it for when I really, really need it. So that’s natural, that’s why we crave high fat, high sugar foods as well, it’s a natural, that’s also why we want to be lazy, believe it or not.

Tim Schnettler: (laughs)

Mark Faries: Because our body wants to conserve that energy. You can watch any of the survival shows, whether they’re clothed or naked. They have at some point in that show to balance conserving energy ’cause they don’t got a lot of food

Tim Schnettler: Right.

Mark Faries: With going out and building something or seeking something or climbing this mountain. The brain has to figure that out because again, we not only want to conserve energy, we crave it, and when we do get it, we store it. So over the years, I’ve heard people, they’ll come up and say, “You know, Dr. Faries, I really want to lose weight, but man, I just crave food.”

Tim Schnettler: (laughs)

Mark Faries: High-fat food, high-sugar food, and I’m like, “Join the club.”

Tim Schnettler: That’s normal.

Mark Faries: That’s human. That’s all of us. We’re designed that way. Or they say, “I wanna exercise more, but I’m just lazy.” “I just wanna go home and relax,” “And when I’ve got that choice to make,” “Should I go to the gym and actually expend energy,” “or stay at home and conserve it,” “I just decide…” And I’m like, “Join the club. That’s all of us.” So we’re not weird, so to speak, or we shouldn’t feel weird or odd that that’s our struggle, because that’s everybody. Now clearly another discussion for another time is, not everybody succumbs to that, and how do we overcome that, which is an interesting discussion. And probably if I had it figured out fully, I’d be rich.

Tim Schnettler: (laughs)

Mark Faries: But I don’t, so we move back to converting fat into muscle cells. But this fat cell is interesting, because it’s so good at storing fat, it’s designed for that, but it’s also hesitant to give it up. So this is why a lot of times we work really, really, really hard, seemingly, for a period of time, and we finally lose some body fat, and then it’s like one weekend we stray, or that one week, and then immediately, it’s right back. Because that fat cell didn’t want to give it up, we finally enticed it to, because we had to, and then eventually, when we did fall off the wagon, so to speak, it was very quick to accept that back.

Tim Schnettler: And I think we’ve all been there, done that. We know that it’s a heck of a lot easier to put it on than it is to take it off.

Mark Faries: There’s no doubt. And that’s why we have a big push for prevention. Don’t get there.

Tim Schnettler: Right.

Mark Faries: And how do we set up environments and social relationships and personal factors and determinants to let people engage a lifestyle with self-control to where they maybe don’t ever get there and can fight that off starting at an early age, et cetera. So you have a fat cell that wants to store, is not willing to give it up. Another unique thing about fat cells is that’s unlike really other cells, including muscle cells, we believe, is that the fat cell, when it fills up, let’s say we have, I don’t know, 100 fat cells. They all fill up. But we’re still eating junk and we’re not being as active, what do we do? Do you know what we do? It’s gotta go somewhere.

Tim Schnettler: Does it create more fat cells?

Mark Faries: It does. It’s called hyperplasia. So the fat cell can get bigger, that’d be hypertrophy. It can get smaller, because we lose fat out of that cell, that would be atrophy. Same as the muscle, same idea.

Tim Schnettler: Right.

Mark Faries: But our third term for today is “hyperplasia.” This idea that we’ll just create new ones. So the body is like, “You fill these up, no biggie,” “I’ll just make another one, and we’ll put some more in” “And it can keep comin’ in,” “no problem, I’ll make another one,” “”You bringing some more in, we’ll make some more.” And it’ll pack it in. It will store it where it has to.

Tim Schnettler: Right.

Mark Faries: And so we have, sort of, a generic total body way of storing fat. We have, generally, differences that we’ve touched on between men and women, for example, generally speaking where women store fat tends to be different than where men. We’ve discussed the hips, that pear shape versus the apple shape, and the importance of the difference and the similarities of those. And so we, the body wants to do that. But when, in the years in our research, where women or men would lose weight, they would get compliments from people, let’s say, or get a comment. In a particular case, they’d say, “Oh, I noticed you’ve lost weight.” “Oh, well how do you know?” “Well it looks, I can tell on your face.” Why is that? Because the body will store fat in the face if it needs to, but it’s maybe more willing to get rid of that sooner than let’s say, for us men around our guts. Does that make sense?

Tim Schnettler: Yeah.

Mark Faries: Or when women, maybe it’s more so than the buttocks and the hips and the thighs. We all are a bit different and individualized, but we all can probably notice when we gain, this is where we notice it first. When we lose, this is where we notice it first.

Tim Schnettler: Mm-hmm.

Mark Faries: So it sort of is a total body experience and this is a good thing, too, which we’ll probably talk about later, this idea of spot-losing fat, in that, when people lose fat cells, the fat in the cells out of their face, they’re not doing face exercises.

Tim Schnettler: (laughs)

Mark Faries: They’re doing something probably total body, expending enough energy to where they increase the demand for the fat cell to break down fat and give us energy. And so it is a total body experience, we do kinda visualize that experience in segments, from the face, from the arms, from the legs, from the belly, et cetera. But that’s the big separation here, is that you have a muscle cell that’s about contracting and moving the skeleton, that can hypertrophy and atrophy, that’s the apple in this analogy.

Tim Schnettler: Okay.

Mark Faries: Then you have the orange, which is the fat cell, which can hypertrophy, get bigger, pack in more fat, it’s designed to do that. It can get rid of fat to provide the muscles with energy. That fat cell then gets smaller, that would be atrophy. But, like we just talked, if we keep packing it in, we’ll keep making more and more and more and more. There is an idea that once we lose the fat from a cell, that it just flattens out and it stays there. That’s the other trick with this. So I’ve lost, lost, lost, lost, but they’re still sitting there. So if I now have 200 fat cells, and let’s say I’ve gotten back to my first original 100,

Tim Schnettler: Mm-hmm.

Mark Faries: There’s the thought that those 100 that I’ve lost fat out of are now just laying there flat, flattened, but they’re still there.

Tim Schnettler: They’re just waiting for you to go off the wagon. Right?

Mark Faries: Exactly. They’re just waiting on that. There is indication that we don’t have time to go into today, but there is indication, remember when we talked, when the muscle cell, when it atrophies, and we say, let’s say I put on muscle, my muscle cell gets bigger from working out, but I stop working out, my muscle gets smaller.

Tim Schnettler: Right.

Mark Faries: Well, we’re not necessarily losing the cells, we can, but in that analogy, that situation, we’re losing the protein inside of that muscle cell. Well, it’s a similar idea with the fat cell, that if we can convince our body that we don’t need those fat cells, we can get rid of ’em. It’s just really hard, and we don’t know how long it takes, and again, another reason for prevention, to try not to ever get to that point. But we’ve seen too many people, even in our research, where they lose fat and its off. And I can tell you, the fat cells aren’t there. There are some that would argue with that, because again, it’s hard to test that, it’s hard to know that for sure, but we have to assume that early on, in the fat-loss phase, that those fat cells are still there, and to kind of be a little note of warning in the back of our brain, that have a fall of the wagon, they might be readily, so watch how much I fall off the wagon. This is kinda one reason, to be honest, that early in the weight-loss challenge, I’m not a huge fan of cheat days,

Tim Schnettler: Yeah.

Mark Faries: Because of that risk. Plus, cheat days can turn into relapse. It’s like, I’ve been exercising, and then I’m gonna go off for a weekend and then I don’t jump back in on it on Monday, and then before I know it, it’s months, years,

Tim Schnettler: Right.

Mark Faries: Down the road. And diet can be very similar. Some can have the self control to do that. They can venture off from a healthy diet for a day, and then next day, no problem, and they’re back on. We all have to sort of gauge where we are in our process of pursuing health and fitness and wellness, what our self control is, and how strong we are to handle those situations.

Tim Schnettler: Mm-hmm.

Mark Faries: But hopefully, that clarifies this idea that we’ve got an apple and an orange here. We’ve got a muscle cell and a fat cell, and they’re not converting to each other. I’d probably like to end with this idea that an apple and an orange, we can eat both, in other words, we can pursue exercise and healthy eating to improve the muscle function, whether it be the size or the strength, or the fitness or the endurance, but at the same time we can also be pursuing to manage our body composition, and particularly the amount of body fat that we have that we talked before, we want to get our body fat to the level that it’s not adversely affecting our health.

Tim Schnettler: Right.

Mark Faries: And so this isn’t about the body image side, which is a different topic as well, we’re talking about health, and we can pursue both, just like we both be eating an apple and an orange, we don’t have to pick one or the other.

Tim Schnettler: But again, it all comes back to, it’s easier to develop that fat cell than it is the muscle, and it all comes back to exercise, making the right choices, and getting out there and doing it.

Mark Faries: It does, and it’s almost like, when you do your exercise, the more specific your goal, the more specific the training. And so, some will go, “I did three sets,” “How come I didn’t get humongous muscles?”

Tim Schnettler: (laughs)

Mark Faries: You didn’t train specifically for that outcome. There is this idea of specificity, and training in a way that gets the results that we want. And so we can get with our exercise professional and find out what that is. Or if not, we can get pretty frustrated. This idea of, “I tried to work out, and it didn’t work.” We have a tendency as humans to rationalize things that way. We globalize. So I’ve seen it all the time. Somebody will do a fad diet, and it doesn’t work, and they’re like, “I tried healthy eating.” “Healthy eating doesn’t work.”

Tim Schnettler: Yeah.

Mark Faries: Well, no, you actually just tried that one diet.

Tim Schnettler: Right.

Mark Faries: But they globalize it to all healthy eating. Or, “I tried exercise and it didn’t work.” Or, “I tried exercise and it hurt my knee.” Well no, you did that type of exercise. It’s not all exercise, or. So we have to be careful. But hopefully it will be helpful to understand this idea of the way fat absorbs much more quickly, it’s harder to lose. Muscle takes a specific effort to get hypertrophy, and there’s probably some balance of those two, with the time that you want to dedicate, with the effort that you want to put in, and being content with some standard that we have, whether it be health or body image or fitness, and the amount of effort and behavior and time that we want to put into those things. Okay, any other thoughts?

Tim Schnettler: No, I think that was great. Once again, we appreciate your input, and hopefully our listeners learned something from this. And maybe it helped somebody change things for the better.

Mark Faries: I hope so. Well, keep pursuing all those positive health and wellness benefits. We appreciate you being here again, and joining us on Health Hullaballoo here at Texas A&M Health Science Center.