Building Muscle and Losing Fat at the Same Time – Is it Possible?

If something seems too good to be true, it probably is too good to be true. Most of us would like to build muscle and lose fat at the same time, but is it possible? Even if it is physiologically possible, can you realistically expect to do it?

It is commonly believed that you can’t increase your muscle mass while being in a caloric deficit. That you need a surplus of energy from the food you eat in order to build more muscle than you break down.

Fortunately, this belief is incorrect. Your body is smart enough to do several things at once. Muscle protein synthesis, the process of adding new muscle tissue, is not solely dependent on calories. With a good training program and a proper diet plan, you can trick your body into adding muscle mass without bulking up.

Muscle Protein Synthesis and Muscle Protein Breakdown, Burning and Storing Fat: A Quick Overview

While in a calorie balance, you build about the same amount of muscle as you break down. At least if you are healthy and live a normal, active life, but without strength training. Muscle protein synthesis and muscle protein breakdown both occur simultaneously, 24/7, from before you are born until the day you die. Physical activity, and the availability of energy and amino acids, control which of these processes dominate at any given moment.

Muscle protein synthesis minus muscle protein breakdown equals muscle protein balance, or just protein balance for short.

  • When your muscle protein synthesis exceeds your muscle protein breakdown, you are in a positive protein balance. Your muscle mass increases.
  • When breakdown exceeds synthesis, you enter a state of negative protein balance, leading to a loss of muscle mass.

The diagram below shows how strength training and your protein intake affects both muscle protein synthesis and breakdown, both at rest and after a workout.

During periods of energy balance, if you don’t lift heavy things, your muscle mass neither increases or decreases over time. You don’t build muscle, but you don’t lose any either. If you eat more calories than you burn, you build muscle. Even if you don’t train. However, without strength training, that increase in muscle mass will be very modest. Something that won’t be modest is your body fat gain. You can’t eat yourself to a muscular physique without training. On the other hand, if you eat less than expend, without training, you will slowly but surely lose muscle mass over time.

You can apply the same principles to your body fat balance. You never actually “burn” fat. Fat is oxidized, but everyone knows what you mean when you say “burn fat”. That’s why we use that somewhat sloppy expression anyway.

Just as with muscle protein, you both store and burn body fat at the same time. When you undereat as well as when you overeat. When you are in a calorie balance, you accumulate as much fat as you burn. That means that your body fat does not increase or decrease. If you increase your calorie intake and eat more than your burn off, you gain weight. On the other hand, if you burn more calories than you eat, your body weight goes down.

What Time Period Are We Talking About?

Every day, both your muscle protein balance and your body fat balance shift from positive to negative, and back again, multiple times. Regardless of your calorie balance over the day as a whole, you lose and gain muscle all the time. After a meal, you build more muscle and store more fat than you break down. In between meals, as you enter a fasted state, you start to break down more muscle tissue and fat mass than you build or store, until your next meal. 

Over the day, week, or month as a whole, synthesis and breakdown are about equal, if you eat as much as you need, no more and no less. In other words, you are weight stable, and so is your body composition.

When someone asks if you can build muscle and lose fat at the same time, reply with another question: what time period are we talking about? The longer the time period, the easier it gets to do both things “at the same time”. If we are talking months, it shouldn’t be all that hard at all. In that case, you will have alternated between gaining muscle mass and losing body fat many times. If you have been training properly and eaten enough protein during this time, you should have improved your body composition. This means that you have built muscle and lost fat at the same time over those months of training and dieting. However, you probably haven’t done so at the same time, if we are talking about the same second, the same minute or the same hour.

If the measurement period is short, it can be quite impossible to do both things at the same time. The hours after a Thanksgiving dinner, you will build more muscle than you break down. However, you will for sure gain body fat at the same time. Over Thanksgiving week as a whole, however, you can lose weight and body fat despite that day of overfeeding, as long as you restrain yourself during the other days.

You Can’t Optimize Both Muscle Mass Gains and Fat Loss at the Same Time

To gain muscle mass, you need to be in an anabolic state. To lose weight and body fat, you need to take in fewer calories than you burn. Losing fat is a catabolic process. You need to be in a calorie deficit. You can’t, unfortunately, get away from that fact.

So, if you want to gain muscle while losing body fat, you need to prime your muscle protein synthesis. You need it to exceed your muscle protein breakdown over the day as a whole. All while staying in a calorie deficit.

That’s not a simple task. Anabolism and catabolism are opposites of each other. If you eat and train haphazardly, your results will also be haphazard.

You will not succeed in building muscle and losing fat at the same time, if you follow a regular weight loss diet without strength training. Losing weight without some form of strength training likely means losing muscle.1

If you decrease your calorie intake to the point of a calorie deficit, your muscle protein synthesis goes down as well.2 In other words, you build less muscle at rest when you eat less. Not only does your protein synthesis in the fasted state and at rest decrease, each meal you eat builds less muscle tissue. The anabolic response to a protein-rich feeding diminishes.

The combination of lower circulating levels of insulin and attenuated signals regulating muscle protein synthesis leads to you building less muscle mass, every hour of every day, if you don’t eat enough.

You Can’t Escape the “Calories In, Calories Out”-Equation… But You Can Manipulate the Results

Can you do anything to prevent this? Fortunately, the answer is yes, and I bet you already know the answer. You need a two-step solution in the form of strength training and a high protein intake.

Your muscle protein synthesis at rest is largely dependent on your calorie intake. However, the increase in muscle protein synthesis following a strength training session is not. It is almost entirely dependent on an abundant supply of amino acids. In other words: the protein you eat.

To synthesize new muscle protein, you do need energy as well. The calorie cost of building muscle is as high as 20% of your entire resting energy expenditure.3

It’s easy to forget that you already have a very large supply of energy: your body fat. Regardless of your body fat levels, you still have plenty of calories stored in your adipose tissue. This energy is continually released, and can be used for different processes requiring said energy. Your bodily functions don’t require immediate access to energy from food.

In addition to amino acids and energy, you also need insulin to stimulate muscle protein synthesis. Despite the common notion that insulin is supposed to be super anabolic, you only need fasting levels of insulin for maximized muscle protein synthesis following a protein-rich meal.4 Claims that insulin is the most anabolic hormone are based on old pig studies, which are not applicable to humans.

If you engage in strength training while in a calorie deficit, you rescue the diminished muscle protein synthesis, restoring it to resting energy balance levels.

Add a protein-rich meal after your workout, and watch muscle protein synthesis soar. The combination of strength training and a protein-rich feeding stimulates muscle protein synthesis substantially. Even when dieting and eating fewer calories than you expend, it increases significantly above levels seen at rest during energy balance.5

You don’t need a massive meal to switch a negative muscle protein balance to a positive following a strength training session. Protein alone is sufficient to make the switch and start building muscle.

Creating a positive protein balance this way means that you build muscle and increase your lean mass following a workout, even though you don’t eat enough for calorie balance. That’s how powerful the anabolic effect of strength training is, when you combine your workout with a protein intake.

So, we have established that yes, you can build more muscle than you break down after a workout, even in an energy deficit, as long as you eat or drink some kind of protein. That’s all well and good, but if it does not mean that you also build more muscle mass than you break down over a longer period of time, it wouldn’t really be relevant in practice. If your body evens out synthesis and breakdown over the day or the week as a whole, your plans to build muscle and burn fat simultaneously would come crashing down like a house of cards. 

What Does the Research Say?

Fortunately, we have plenty of scientific research showing that it is quite possible to accomplish both things at the same time, even over a longer period of time.

Beginners and Untrained

When you have just started training, your capacity to build muscle is at its peak, even if you don’t have the greatest of genetics. If you also have more body fat than you really need, you shouldn’t have any issues at all.

  • Overweight subjects lost several kilograms of fat while gaining a lot of muscle in a 14-week long study, while engaging in both strength and endurance training.6
  • Elderly women eating less than 1,000 calories a day over the course of 3 months lost 16 kilograms of body weight. At the same time, they increased their muscle thickness with the help of strength training.7
  • Overweight police officers were placed on a low-calorie diet supplemented with protein shakes for 12 weeks. During this time, they also engaged in a strength training regimen, and lost 4.2 kilograms of body fat while gaining 4 kilograms of fat free mass.8

As you can see, it is quite feasible for an untrained beginner to expect both gains in muscle mass and fat loss when taking up strength training.

What About Resistance Trained Individuals?

What if you are already at least reasonably well-trained? Can you accomplish the same feat? You might not be overweight, just wanting to get in shape and lose some body fat without sacrificing your ability to continue gaining muscle mass during this time.

The answer is yes here as well. However, it won’t be quite as easy. You won’t see any dramatic increases in muscle mass in a few months while losing 10 kilograms of body fat. But you can still gain some muscle mass while losing fat. The scientific literature offers support for your endeavours as well.

  • Italian elite gymnasts eating less than 2,000 calories a day lost weight, reaching body fat levels close to 5% after a month of regular training. We are not talking about recreational exercise here, but rather 30 hours a week of elite level gymnast training. Despite extremely low body fat levels and a large calorie deficit, they still managed to gain half a kilogram of muscle during this month.9
  • Twenty-four highly trained athletes reduced their calorie intake by 20%, creating an energy deficit. They lost both body weight and body fat over the course of an 8 to 9-week long study. During this time, they engaged in strength training 4 times per week, and managed to increase their fat free mass by 2% despite the weight loss and the underfeeding.10
  • Female International Federation of Bodybuilding and Fitness (IFBB) athletes increased their fat free mass during competition preparation. Not all of them did, but at least some of them managed this feat. REF Before you say steroids, the scientists closely monitored the hormone levels of the participants. Anabolic hormone levels decreased substantially (a natural consequence of calorie restriction), which indicates that drugs were not involved in the results.11
  • Several relevant studies feature highly trained rugby players. In one of these studies, 24 young elite players lost a little more than a kilogram of body fat during pre-season training while increasing their fat free mass with the same amount. REF However, they might simply have regained muscle mass lost in between seasons, if they took a break from training during that time. In that case, muscle memory would explain at least some of the results.12

As you can see, even trained individuals can lose body fat while gaining muscle mass. However, the fact that something is possible does not necessarily guarantee that it will happen. This is apparent in a case study of a natural bodybuilder during a competition prep. He lost almost as much muscle mass as body fat during a 14 week contest diet, even though he trained properly and followed a strict diet plan.13

Fat-free mass and fat mass in a natural bodybuilder dieting for 14 weeks, going from 14% body fat to 7%.

The Importance of Eating Plenty of Protein

Your training is not the only thing determining if your attempts to recomposition your body this way will end in success or failure. As we mentioned earlier, your protein intake is an important factor. Two well-controlled studies demonstrate this quite effectively.

In the first study, 40 young men reduced their calorie intake by 40% over the course of a month. Six days a week, they combined strength training and high intensity interval training. Half the subjects ate 1.2 grams of protein per kilogram of bodyweight and day, while the rest ate double that amount. This means that all participants exceeded general recommendations for protein intake. The high-protein group increased their muscle mass significantly. The group that ate 1.2 grams of protein per kilogram of bodyweight and day did not lose any muscle, but they didn’t gain any either. In addition, the high-protein group lost more weight and body fat.14

A similar study divided 17 female fitness athletes into two groups, a high-protein group and a low-protein group, during 8 weeks of strength training. Both groups were in a negative energy balance. The high-protein group ate around 1,800 calories per day, while the low-calorie group only ate a little more than 1,400. Even though the high-protein group ate more calories than the low-protein group, they lost more body fat. In addition, they managed to add 2 kilograms of fat free mass. The low-protein group did not increase their fat free mass significantly.15

In summary: nothing of what we have discussed breaks the laws of thermodynamics. Calories in minus calories out is still valid. However, that equation does not say anything about what your body uses those calories for. By engaging in strength training and keeping your protein intake high, more of what you eat can be used for building muscle. You can build muscle and lose fat both if you are untrained and if you are already a highly trained athlete. You are in for more of a challenge if you are past the beginner’s stage in your training career, though.

Keep Your Expectations in Check

You can lose body fat fast. Really fast. The larger your calorie deficit, the faster you lose weight and body fat, both if you are untrained or trained. Gaining muscle mass is much harder and takes a much longer time. When you are just starting out, your results can come pretty rapidly, but not at the same rate as your ability to lose fat. If you are already well-trained, gaining a few hundred grams of muscle a month is great. On the other hand, you can easily lose several kilograms of body fat during the same month.

Adjust your expectations according to this. Don’t expect to be able to replace a lost kilogram of body fat with a kilogram of muscle mass. That is not realistic.

If you are not overweight, you have to accept that you can’t gain muscle mass at the same rate you can lose fat. The gymnasts in the study we mentioned earlier did gain muscle while reaching extremely low levels of body fat matching those of a stage ready bodybuilder. However, the average person should probably not expect results like that. The leaner you get, the harder it is to gain muscle while continuing to lose fat. The last month of a pre-contest diet, most bodybuilders focus on losing as little lean mass as possible, for example, not gaining more. Your energy availability and hormonal status do not promote anabolism under conditions like that.

How to Build Muscle and Lose Fat at the Same Time

While this article is not meant to be a detailed guide on how to go about gaining muscle mass and losing body fat simultaneously (that could become an article on it’s own), here are some pointers:

  • Eat plenty of protein. At calorie balance or in a surplus, 1.6 grams of protein per kilogram of bodyweight and day is enough to promote maximal gains in muscle mass for almost everyone. If you increase that to 2.2 grams per kilogram and day, you cover all your bases for sure, even if you are an elite strength athlete or competitive bodybuilder.16 17 However, if you are on a fat loss diet, eating fewer calories than you burn, that amount of protein might not be enough. You might have to increase it even further, up to 3.1 grams per kilogram of bodyweight and day, depending on your body fat levels and the magnitude of your calorie deficit.18 19
  • Hit the gym. No surprises here. One thing to keep in mind is that your ability to recover from your workouts is diminished on a diet. This means that you should follow an individualized training program that adjusts for this fact. The training program you used when you were bulking up might not be ideal.
  • Don’t spend half the day in the gym. While strength training is the most anabolic tool you have access to, avoid marathon sessions that break your muscles down as much as they build them up. Focus on exercises that give you the most bang for your buck. That means compound movements where you can use heavy loads and hit more than one muscle group at a time.
  • Gear your workouts towards building muscle, not burning fat. Your training program should be designed to stimulate muscle growth, not to burn fat. You handle that part in the kitchen. Exercise that “burns fat”, like endurance training, offers, at best, a modest effect on body composition and fat loss. In addition, excess aerobic exercise can inhibit the anabolic effects of strength training. That’s the last thing you want, when you already have catabolic effects from your calorie deficit to deal with.
  • Don’t eat too little. The less you eat, the faster you lose body weight and body fat. Strength training is such a powerful muscle-building activity that it can prevent the loss of muscle mass even during large energy deficits. You do need an energy deficit to lose body fat, but gaining muscle mass at the same time is a different kettle of fish. While you can do it, like the gymnasts we talked about earlier did while training 4 hours a day, it’s much more difficult. If you want a reasonable chance of success, it’s probably smart to aim for a moderate calorie deficit.

What about carb cycling? Carb cycling is a popular method intended to increase your ability to gain muscle while losing body fat, simply by adjusting your carbohydrate intake depending on your activities. On training days, you eat more carbs in order to perform your best and increase your insulin levels. On rest days, you decrease your carb intake, induce a greater calorie deficit, and lower your insulin levels, thus burning more fat.

In theory. Very few studies, if any, support this method to circumvent the “calorie in minus calorie out”-equation. Carbohydrates do not promote any extra muscle protein synthesis compared to protein alone. Fasting levels of insulin are enough to max out your protein synthesis response to a protein rich meal. How you distribute your calories from carbohydrates and fat at a certain energy intake  seems to have a minimal effect on your body weight and body composition.

If you want to experiment with carb cycling, feel free to do so. It is most likely not detrimental in any way. I can attest to getting a better pump and performing better in the gym by carb loading on training days and compensating with a lower carb intake on rest days. However, there is no scientific evidence that this leads to either greater fat loss or greater gains in muscle mass.

Do You Build More Muscle if You Bulk First, Diet Later?

Maybe. An energy surplus makes it much easier to gain muscle mass. If you keep your overfeeding under control, you don’t have to gain too much excess fat at the same time.

It is pretty easy to maintain the muscle you have gained during a bulk when you switch to dieting your fat away. Maintaining muscle mass during a cutting diet is much easier than trying to gain muscle.

So no, it is probably more effective in the long run to alternate periods of moderate overeating with periods of dieting. It might also be the easier alternative psychologically. Maintaining a calorie deficit over longer periods of time can be challenging not just for your body, but for your brain as well.

However, when you bulk and cut the traditional way, you invariably gain body fat during parts of the year. If you are not comfortable with that, staying in a calorie balance during most of the year and peaking once or twice a year might be an alternative.

In addition, even if you give building muscle and burning fat at the same time a go, you don’t necessarily have to do it year-round. If nothing else, now you know that you don’t have to forego gaining muscle during a cutting phase.


Can you gain muscle and lose fat the same time?

Simple answer: yes.

More complex answer: maybe. You can’t really say for sure that a certain individual will be able to. It depends on many physiological and behavioural factors.

I’m sure most of us wish we were born with better genetics for building muscle. At the same time, many blame their genetics when they don’t get the results they want from their training, when they really shouldn’t. More often than not, the lack of results stem from not training properly or hard enough, or from a bad diet and lack of sleep and recovery, rather than from poor genetics. Spending more time on the phone than lifting in the gym does not build muscle. Eating poorly and too little does not build muscle. If you want to gain muscle while losing fat, these things become even more important.

That being said: not everyone is genetically blessed. If you really have to fight for every gram of muscle mass you manage to put on, you will find it hard to do both things simultaneously. At least compared to someone with biceps that grow just by looking at the barbell. The same thing goes for your diet. Not everyone utilize the food they eat in the same way. Some people build more muscle, others store more fat, at the same calorie intake.

Other factors, like your hormones, how well you sleep, and your entire life outside the gym, including stress and things like that, also affect your chances to gain muscle while losing fat.

If you succeed in doing both things at the same time depends on many things. Some work for you, others against you. This makes it impossible to say if you can do it … before you try. Physiologically, it is quite possible. And if you have at least somewhat decent genes, and the will and discipline to accomplish it, you probably can.

Read more:


  1. Nutrition Reviews, Volume 68, Issue 7, 1 July 2010, Pages 375–388. A systematic review of the separate and combined effects of energy restriction and exercise on fat-free mass in middle-aged and older adults: implications for sarcopenic obesity.
  2. The Journal of Nutrition, Volume 140, Issue 4, April 2010, Pages 745–751. Acute Energy Deprivation Affects Skeletal Muscle Protein Synthesis and Associated Intracellular Signaling Proteins in Physically Active Adults.
  3. Exercise and Sport Sciences Reviews: April 2007 – Volume 35 – Issue 2 – p 50-55. Human Muscle Protein Synthesis After Physical Activity and Feeding.
  4. J Physiol. 2012 Mar 1; 590(Pt 5): 1049–1057. Muscle protein synthesis in response to nutrition and exercise.
  5. Am J Physiol Endocrinol Metab. 2014 Apr 15;306(8):E989-97. Reduced resting skeletal muscle protein synthesis is rescued by resistance exercise and protein ingestion following short-term energy deficit.
  6. Medicine & Science in Sports & Exercise. 29(9):1170-1175, September 1997. Effects of cross-training on markers of insulin resistance/hyperinsulinemia.
  7. The American Journal of Clinical Nutrition, Volume 58, Issue 4, October 1993, Pages 561–565. Muscle hypertrophy with large-scale weight loss and resistance training.
  8. Ann Nutr Metab 2000;44:21–29. Effect of a Hypocaloric Diet, Increased Protein Intake and Resistance Training on Lean Mass Gains and Fat Mass Loss in Overweight Police Officers.
  9. J Int Soc Sports Nutr. 2012; 9: 34. Ketogenic diet does not affect strength performance in elite artistic gymnasts.
  10. International Journal of Sport Nutrition and Exercise Metabolism, Vol 21: Issue 2. Pages 97-104. Effect of Two Different Weight-Loss Rates on Body Composition and Strength and Power-Related Performance in Elite Athletes.
  11. Front. Physiol., 10 January 2017. The Effects of Intensive Weight Reduction on Body Composition and Serum Hormones in Female Fitness Competitors.
  12. International Journal of Sport Nutrition and Exercise Metabolism, Volume 26: Issue 1. Pages: 1–7. Increasing Protein Distribution Has No Effect on Changes in Lean Mass During a Rugby Preseason.
  13. J Int Soc Sports Nutr. 2015; 12: 20. A nutrition and conditioning intervention for natural bodybuilding contest preparation: case study.
  14. The American Journal of Clinical Nutrition, Volume 103, Issue 3, March 2016, Pages 738–746. Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial.
  15. International Journal of Sport Nutrition and Exercise Metabolism. Volume 28: Issue 6. Pages: 580–585.Effects of High Versus Low Protein Intake on Body Composition and Maximal Strength in Aspiring Female Physique Athletes Engaging in an 8-Week Resistance Training Program.
  16. British Journal of Sports Medicine, 2017. Volume 52, Issue 6. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults.
  17. The Journal of Nutrition, Volume 147, Issue 5, May 2017, Pages 850–857. Indicator Amino Acid–Derived Estimate of Dietary Protein Requirement for Male Bodybuilders on a Nontraining Day Is Several-Fold Greater than the Current Recommended Dietary Allowance.
  18. International Journal of Sport Nutrition and Exercise Metabolism. Volume 24: Issue 2. Pages: 127–138. A Systematic Review of Dietary Protein During Caloric Restriction in Resistance Trained Lean Athletes: A Case for Higher Intakes.
  19. Journal of the International Society of Sports Nutrition volume 14, Article number: 16 (2017). International society of sports nutrition position stand: diets and body composition.
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Andreas Abelsson

Andreas has over 30 years of training experience and is a highly appreciated writer and educator on exercise, fitness, and nutrition. Few people stay more up to date and have a better grasp of the field of exercise science than Andreas.