Episode 260 - How to Gain Muscle While Losing Body Fat

Can you gain muscle while losing body fat at the same time, or is body recomposition just a clickbait headline?

For years the advice has been that you have to pick one. Eat in a calorie deficit and lose body fat, or eat in a calorie surplus and build muscle. A brand new study published in the European Journal of Applied Physiology in April 2026 says the picture is more interesting than that, and it is already being butchered all over social media. I break the whole paper down for you. What the researchers did, what they actually measured, and the bits the headlines have quietly skipped over. Then I do the part that matters most, which is translating a study done on young resistance trained lifters into what it means for someone swimming, biking and running six days a week.

IN THIS EPISODE

• What body recomposition actually is, and why it is not the same thing as losing weight
• What the 2026 study did, and what happened to all three groups over 10 weeks
• Why an increase in fat-free mass does not automatically mean a kilo of new muscle
• The training detail that did just as much work as the nutrition did
• Whether you really need 2.5 grams of protein per kilo of body weight a day
• Why the size of the calorie deficit matters far more than most triathletes think
• Where this study stops transferring the moment you apply it to endurance training
• Who is well placed to recomp right now, and who is better off picking one goal
• The 4 things I would start with if body recomposition is your goal

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Episode Transcription

Episode 260: How to Gain Muscle While Losing Body Fat

Welcome to the Triathlon Nutrition Academy podcast. The show designed to serve you up evidence-based sports nutrition advice from the experts. Hi, I'm your host Taryn, Accredited Practicing Dietitian, Advanced Sports Dietitian and founder of Dietitian Approved. Listen as I break down the latest evidence to give you practical, easy-to-digest strategies to train hard, recover faster and perform at your best. You have so much potential, and I want to help you unlock that with the power of nutrition. Let's get into it.

If I told you that you could lose body fat while gaining muscle at the same time, would you believe me? Because for years we've been told you have to choose. You either eat in a calorie deficit and lose body fat, or eat in a calorie surplus and gain muscle mass. And if you want to do both, apparently that's impossible.

[00:00:20] Well, today we're going to dive into the research and talk about why that isn't particularly true. And I think this is something that a lot of triathletes, heck, any active person, gets wrong. If you're in the Southern Hemisphere, we are hurtling towards our race season, and body composition becomes a really important element in our minds in order to race well.

[00:00:39] And if you're in the Northern Hemisphere, then you're coming out the other side of your season, and you're moving into that period of time where maybe winter pudding is a little bit more plentiful. But you're hopefully already starting to think about what you want to work on over that time period when it's dark and cold in your off-season so you are ready to go and building the foundation for your season next year.

[00:01:00] And if one of your goals is to lose some body fat while becoming stronger, this is actually a really good time, no matter where you are in the world, to start thinking about how you're going to do that and get your ducks in a row. Because body recomposition is absolutely possible, but there are some very important caveats.

[00:01:19] As triathletes, it's a very delicate balance because you want to be able to fuel your training, otherwise you're going to fall into a massive heap. And there is a brand-new study that gives us some really interesting information and foundations to go on around how to do this specifically. So today I'm going to break down that paper, tell you exactly what they did, what they found.

[00:01:39] As an Advanced Sports Dietitian, I'm going to break that down and translate that into something practical and what it means for you as a triathlete. Because there's a really big difference between reading a study that was done on young resistance-trained adults and then just applying that blindly to somebody that swims, bikes, and runs six to seven days a week.

[00:02:01] So let's get into it. Firstly, what is body recomposition? Essentially, it means that we're changing the ratio of fat mass to lean mass. So in practical terms, we're talking about losing body fat while maintaining or increasing our lean muscle tissue. And this is where things get really interesting in more modern literature because traditionally we treated muscle gain and fat loss as completely separate goals.

[00:02:27] If you want to build muscle, the approach is eat more, train hard, gain weight so that your body is in a happy, comfortable, and safe fed state to be able to lay down new tissue. Then if you've gained fat in that process, then you do a shred and deliberate diet afterwards to take that off. Bodybuilders go in these cycles of muscle hypertrophy, doing everything they possibly can to lay down new muscle tissue.

[00:02:55] And if you want to lose body fat, the traditional approach that everyone does is eat less, create a calorie deficit, and lose weight. And hopefully, if you're doing that right, you're preserving your lean muscle tissue in that process. But more often than not, it's not done well, it's done too fast, it's done too aggressively, and your muscle mass is lost in that process.

[00:03:19] And there's logic behind both of those approaches. But what we've learnt over time is that the human body is far more complicated than simply saying, "Calories in, calories out." If you're in a deficit, you can't gain muscle mass. You still need to obey the laws of thermodynamics, but that doesn't mean every tissue in the body responds or has to respond in exactly the same direction.

[00:03:44] You can lose energy-rich fat tissue while simultaneously increasing fat-free tissue, and that essentially is what body recomposition is. So this paper I'm talking about today, and I'll link it below if you do want to go and nerd out, was published in the European Journal of Applied Physiology in April 2026.

[00:04:03] A couple of the big names on that paper were Alan Aragon and Brad Schoenfeld. If you've read any of the papers in this space, those names will be familiar to you. The authors wanted to compare these two different nutrition approaches in resistance-trained people with the goal of body recomposition.

[00:04:24] There were 30 participants that completed the study, and they were young adults between 18 to 35. They had at least a year's experience of resistance training, so they weren't complete beginners. And this is an important point, because they weren't untrained, but they also weren't elite bodybuilders who have been lifting weights for 15 years.

[00:04:42] They were somewhere in the middle. They had some experience, but not lots. 26 of the 30 participants were men. There was four token women. So we do need to be cautious when we're applying these results directly to all subsets of the population. Now, the participants were split into three groups. The first group- Ate 250 calories below their estimated maintenance calories.

[00:05:06] The second group ate approximately maintenance calories, so weren't in a deficit, weren't in a surplus. And both of those groups had nutrition support to be able to do that. And the control group continued on with their usual diet without any supervision. All three of those groups did the same resistance training program.

[00:05:26] It was four days a week for 10 weeks. The two nutrition intervention groups were also prescribed 2.5 grams per kilo of body weight protein per day. And this is where the results get really interesting. The group in the 250-calorie deficit lost 2.94 kilos of body fat, which is 6.48 pounds, over the 10 weeks, and they also increased their fat-free mass by about one kilo.

[00:05:54] Let that sink in for a second. Almost three kilos of body fat down while fat-free mass went up about a kilo. The maintenance group, eating calories at estimated maintenance, also increased their fat-free mass by just under one kilo, and they had a similar reduction in fat mass of 1.41 kilos. The control group, essentially no change in their body composition.

[00:06:20] So both nutrition interventions produced these improvements in body composition compared to the control group, and the deficit group produced the largest reduction in fat mass. So what this study actually shows is that both supervised approaches beat doing nothing at all. And honestly, that gap between eating maintenance calories and eating 250 calories below maintenance was not that great.

[00:06:45] It's only about one and a half kilos difference in fat mass over a 10-week period. So before you hear those numbers and go, "Awesome, Taryn, I just need to eat two and a half grams per kilo of protein a day, and I'm going to gain a kilo of lean mass and lose some body fat in the process over 10 weeks," please stop, because that is not what this study tells us.

[00:07:05] And this is where you need to be really careful with the interpretation and not believe the clickbait all over social media. Use your brain and just think critically for a second. The researchers measured body composition using DEXA. DEXA is a really useful tool for measuring body composition change over time.

[00:07:24] But when they say fat-free mass increased by about a kilo, that does not directly equate to one kilo of new skeletal muscle tissue because fat-free mass is what you're made up of, everything that doesn't include fat. Okay? Fat-free mass. So that includes, yes, your contractile muscle, but it's also bone, organs, water, muscle glycogen.

[00:07:49] Depends how much you've got of that in storage, which matters because over 10 weeks, an increase could be water. It could be more glycogen rather than new lean muscle tissue. So we need to be really cautious interpreting those results as definitely muscle tissue. The authors themselves acknowledge that limitation and explain that the techniques like adding an MRI or a CT or an ultrasound could provide better information about true skeletal muscle change.

[00:08:19] So I would call this an increase in fat-free mass consistent with body recomposition, rather than saying these people gained exactly one kilo of new muscle. And that distinction matters because if we're going to talk about the research, we need to dive into the weeds and talk about what the research actually measured, not what makes the best clickbait headline, which is what is happening with this paper.

[00:08:43] So how did they do this? Let's talk about the really important part, because this wasn't just, eat lots of protein and magically gain muscle. The participants were doing a structured resistance training program four days a week. And they completed three sets of 10 repetitions for each exercise that they did.

[00:09:01] And the load was adjusted, so they're generally finishing with one to two reps in reserve. And if you don't know what that means, that means that it's heavy. It means that you cannot physically lift it any more than maybe once, if you're lucky twice, at the end of a set. And importantly, the loads were progressively adjusted throughout the program, throughout the 10 weeks.

[00:09:27] So they weren't just going into the gym and moving the same weights around for 10 weeks or doing body weight exercises and a few dumbbell lunges and calling it strength training. The training stimulus was progressing, and that is a huge part of body recomposition, and it's part of the conversation that people often forget.

[00:09:46] If you want your body to build muscle tissue, you need to provide the reason and the stimulus for your body to build muscle tissue. Nutrition doesn't replace the training stimulus. A protein shake doesn't replace the training stimulus. Resistance training provides the signal, and then nutrition provides some of the resources required to adapt to that signal.

[00:10:08] And in this study, both of those things were there. There was one more thing in the training data that I think it's also worth knowing. Over the 10 weeks, the maintenance calorie group, they actually increased their lower body training load about 10 times more than the other two groups did. So it isn't clean to say that nutrition did all the work here.

[00:10:29] The training changed as well, and it changed a lot in one of those three groups. One more piece that made me laugh a little when I read this, the unsupervised control group, the ones who got no nutrition help whatsoever, they had the biggest strength gains out of all three of the groups. And the authors admit that that may have been a fake result.

[00:10:51] No offense to the control group. Now, let's talk about protein because the study used a, quite a high amount, two and a half grams per kilo of body weight. That's a lot of protein, and I can hear you thinking, "All right. Cool, Taryn. Maybe that's the magic number. I'm going to crank it up to that and see how I go."

[00:11:06] I don't think that that's the conclusion that you should take from this study as a triathlete. Previous research suggests around 1.6 to 2.2 grams of protein per kilo body mass a day is sufficient for, you know, muscle hypertrophy. Higher intakes can be useful when you are dieting, putting yourself into a calorie deficit, because having a high intake of protein or an increased intake of protein can help maintain your lean mass while you're trying to drive some fat mass loss.

[00:11:37] And also, it can fill you up so that you eat less crap. Once you're hitting really high intakes of, like, upwards of 2.2 to 2.5 grams per kilo, eating extra protein may not necessarily provide any additional benefit. So please don't take this episode of the podcast or go and read that paper and decide that you need to eat two and a half grams per kilo body weight a day of protein.

[00:12:03] Because you're a triathlete, okay? You're not following a program with four strength sessions in a week and not much cardio, and that distinction matters for you. You don't have this unlimited calorie budget to fit all that extra protein in with everything else you need to do. You need carbohydrate to support swimming, cycling, running You need enough total energy to support your training so that you don't end up in low energy availability.

[00:12:30] You need to eat enough fat in your overall diet, and you need to eat enough protein to support lean muscle tissue repair and adaptation. So the goal is not, "Hey, how much protein can I possibly cram into my diet?" The goal is, "How do I distribute my energy, my macronutrients," and don't forget about the micros, "so that my entire training program is supported while I'm still moving towards my body composition goals?"

[00:12:58] And that's a very different question. That is a type of question I answer and things I work with for my athletes in the Triathlon Nutrition Academy program every single week, and the answer for each one of those individuals is always different. The other thing I really like about this study, and maybe you could take this piece away, is the size of the calorie deficit that they were in.

[00:13:19] It's only 250 calories a day or about 1,000 kilojoules. And it's a really important point because when people decide to lose body fat, you're like, "Right. That's it. Going on a diet," the first thing that you do is you drastically slash calories. You cut breakfast. You cut snacks. You cut carbs. You start throwing in some extra training sessions and doing cross-training.

[00:13:43] You become obsessed with the scales, both the kitchen scales for weighing food and the standing ones to weigh your body. And suddenly you're trying to train for a triathlon while eating like you're preparing for a body sculpting competition, and this is not what I want you doing. The researchers deliberately used a more modest deficit because more aggressive energy restriction can increase the risk of losing lean mass, particularly in more trained people and more lean people.

[00:14:11] And this is exactly why I don't like, and doesn't always work, the eat less, move more philosophy. Because your goal is not to simply make the number on the scales go down. If you're a triathlete, your goal is to change your body composition without destroying your training, and they are not the same thing.

[00:14:29] And here's where I think this research becomes really interesting for you. The study was not conducted in triathletes, okay? It was conducted in young resistance-trained people. The calorie deficit group were also prescribed around two and a half grams per kilo of carbohydrate per day. So for an 80-kilo person, that's around 200 grams of carbs.

[00:14:48] Now, an 80-kilo triathlete in a regular training block needs way more than that, somewhere around like 400 to 650 grams of carbs, depending on the training load. So they were eating roughly a third Of what you need. So we can't take the results from this paper and go, "Great, this is exactly what happens when a triathlete goes into a deficit."

[00:15:11] That is not confirmed. But what we can take from it is the principle. If you're trying to drive some body fat loss while maintaining or increasing your lean mass, you want to create the conditions and the environment that are going to make those adaptations more likely to occur. And that means a sensible energy intake, adequate protein Eating carbohydrate to support the type of training that you're doing, a proper resistance training stimulus, and enough recovery.

[00:15:40] Can you notice what's missing? Extreme restriction was not on that list. Neither is hours of punishing yourself. The other thing to think about is who is body recomposition actually suited to? And that's another really important part of this paper, I think, because the ability to recomp isn't the same for everyone.

[00:15:59] If you're relatively new to resistance training, if you've had a long break from training, if you have more body fat to lose, you potentially have a much greater opportunity to lose fat while gaining lean mass. As you become more advanced, more muscular, and leaner, the opportunity becomes smaller, and this makes sense.

[00:16:21] Your body has less room to make dramatic change. The participants in this study had an, an average of around one and a half years of resistance training experience, and they were sitting at around 24.8% body fat when the study started. That level is still within the healthy weight range, and it's at a level that makes losing body fat relatively easy to achieve.

[00:16:45] An experienced leaner group to start with would have probably shown weaker results. So if you're already really lean, highly trained, and close to your genetic potential for muscle growth, trying to simultaneously gain a significant amount of muscle while also losing a significant amount of fat is probably the most effective or efficient strategy for you.

[00:17:09] You may be better off choosing a more specific goal for a period of time. But if you're an age group triathlete who has never really done structured strength training, or if you've spent years doing endurance training without really paying much attention to your nutrition, or you've finished a season and you've got a few spare months up your sleeve where you could actually prioritise strength, you may have a really good opportunity here, and this is why timing matters.

[00:17:34] We are sitting in a really interesting point in the triathlon calendar right now. If you're in Australia, we're moving into race season, and if you're in the Northern Hemisphere, you're either finished or coming to the end of your season. So either way, there is an opportunity to think about what comes next.

[00:17:49] For you, it might be, "I want to get stronger so I don't fall apart in the run," or, "I need to lose some body fat to take the pressure off my joints," or, "I want to improve my body composition, but without sacrificing performance to do it." Or it could be just simply, "I want to feel like my nutrition is not constantly fighting against my training program."

[00:18:11] These are the things I want you to start thinking about, because you don't want to wait until January to get started. You don't want to wait until your next race is finished to get started, and you definitely don't want to wait until you, you've decided that what you're doing is not actually working for you anymore.

[00:18:26] If body recomposition is one of your goals, then right now is the perfect time to start. So if you came to me and you said, "Hey, Taryn, I want to lose some body fat while gaining or maintaining my lean muscle mass," what would you do? I'd start with four things. Number one, get your energy intake right. It's not as low as possible.

[00:18:45] We want enough energy to train, recover, and adapt from your training while creating the perfect environment and conditions for fat loss if fat loss is actually appropriate for you right now. And that number is highly individual, and the timing is highly individual. The 250-calorie deficit is not a prescription for every athlete.

[00:19:05] It's a great example of what a moderate deficit looks like in this particular study for young whippersnappers without changing hormones. Number two, get your protein intake right. You do not need to eat as much as 2.5 grams per kilo of body mass a day. You don't need to live on chicken breast and protein shakes.

[00:19:25] But you do need to consume consistently enough protein on the daily basis to meet your needs and support your goals. And if you're in an energy deficit, protein becomes even more important to maintain your lean mass while you do that. Number three, keep carbohydrate in the picture. God, it is not the enemy.

[00:19:43] It is the first macro that people cut when they want to try and drive some fat loss. This is the part that I really want you to hear. If you cut your carbohydrate down too low because you're trying to lose body fat, you make your whole body stressed You make training harder for no real good reason, and it makes fat loss harder.

[00:20:04] Your endurance training requires carbohydrate, and I'm not interested in creating this perfect body recomposition plan that works on paper but leaves you unable to be able to complete your key triathlon training sessions. If you can train harder, you actually burn more calories, so you've got to be smart about your approach here.

[00:20:23] And number four, actually strength train. Get in the gym, not occasionally, not when you have time, not some random 20-minute body weight circuit. If building or maintaining muscle is important to you, particularly as you're getting older, resistance training needs to be a structured and deliberate part of your training program.

[00:20:44] It doesn't have to be four times a week, and ideally, it needs to progress, so you've got that progressive overload. If you need help with trainers that are specialists in dealing with triathletes and know that we also have to swim, bike, and run and not be so sore that we can't function, then send me a DM on Instagram and I can point you in the right direction, @dietitian.approved, spelt with two Ts.

[00:21:07] So let's come back to the question I asked right in the beginning of this episode. Can you gain muscle while losing fat? Yes, body recomposition is a real physiological phenomenon, and this 2026 study adds to the evidence supporting that. In the study, people consuming high protein while doing structured resistance training were able to increase their fat-free mass while reducing fat mass, including the group that were on maintenance calories and the group that were 250 calories below maintenance.

[00:21:40] But that doesn't mean everyone can gain a kilo of muscle and lose three kilos of fat in 10 weeks. It doesn't mean calories don't matter either. It doesn't mean you need two and a half grams per kilo of protein per day of body weight, and it also doesn't mean you should slash your food intake and increase your cardio.

[00:21:59] What it tells us is that your body is capable of changing its composition in more than one direction at the same time, and the likelihood of doing that is going to depend on where you're starting, your training status, your body composition, your nutrition, your training stimulus, and your ability to recover and adapt.

[00:22:20] And this is exactly why I don't believe in generic meal plans, and you won't find a free downloadable one on my website for that reason. Because the nutrition strategy that works for a 23-year-old resistance-trained male participant in a 10-week research study isn't automatically the nutrition strategy that is going to work for a 45-year-old age group triathlete doing 10 to 15 hours of endurance training a week.

[00:22:45] You need to look at the whole picture, think critically, and then apply that to your nutrition. All right. So Taryn, I understand the theory, but I have absolutely no idea what this is going to look like for me. Maybe you've already had a crack at this, and you went too hard, too fast, and you ended up feeling like what I call the tired triathlete, where you need a nap after your long rides.

[00:23:07] You start searching for junk food in the afternoons to give you a pick-me-up because you're feeling so fatigued. You're craving fast, simple sugars all the time because you're so hungry and starving. You're exhausted by the end of the week. You're feeling constantly fatigued, and you're sore, and you're irritable If you need help with working out how many calories you actually need on a daily basis, when to create a deficit and when not to, how big that deficit should be for you, and how to protect your training while you go about it, how to spread your protein intake across the day in real food that doesn't mean you're necking protein bars and protein shakes, how to fuel your key triathlon training sessions so that they don't fall apart, and then holding all of that together across a training week that looks different every single week, that is exactly what I can help you with in the Triathlon Nutrition Academy.

[00:24:01] It's me teaching you how to work out your numbers against your own training program in your own body, and then I will be there every week while you actually do it. Because whether you're heading into your race season or heading into your off-season, this is a really good time to stop winging your nutrition and build a strategy around your goals.

[00:24:21] Let's not wait for January to do that. If body recomposition is one of your goals, don't wait until you are desperate to change it to start. The slower you do it, the more successful you'll be. The academy only opens a few times a year, so head to dietitianapproved.com/academy to get your name on the list for the next cohort.

[00:24:40] This is the only way to work with me on your nutrition, and nine months from now, you'll know exactly how to fuel for triathlon and why. It's one investment, but it lasts a lifetime. See you next week.

Thanks for joining me for this episode of the Triathlon Nutrition Academy podcast. I would love to hear from you. If you have any questions or want to share with me what you've learned, email me at [email protected]. You can also spread the word by leaving me a review and taking a screenshot of you listening to the show. Don't forget to tag me on social media, @dietitian.approved, so I can give you a shout out, too. If you want to learn more about what we do, head to dietitianapproved.com. And if you want to learn more about the Triathlon Nutrition Academy program, head to dietitianapproved.com/academy. Thanks for joining me and I look forward to helping you smashed in the fourth leg - nutrition!