For many people, “losing weight” is a bit of a misnomer in terms of their actual fitness goal. In reality, in many cases, people who say they want to lose weight actually want to lose body fat and gain muscle.
The common wisdom among fitness circles suggests that these goals belong to separate realms. You’re either in a calorie surplus, primed for muscle growth, or in a deficit, aiming to lose fat. But is this dichotomy as rigid as it seems?
By definition, an energy deficit restricts the energy available for the body, including muscle repair and growth.
However, achieving simultaneous muscle gain and fat loss may be possible, but it demands patience, precision, and timing.
Let’s delve deeper to understand the nuance within the debate.
Can You Build Muscle In A Calorie Deficit?
As we have alluded to, there are scenarios in which you can build muscle in a calorie deficit; in order to understand it better, let’s be clear on how muscles grow.
In order for muscles to grow, which is termed hypertrophy, they need a stimulus and the proper environment or resources.
The stimulus can come from the stress applied to your muscles through resistance training or lifting weights.
Resistance training causes microscopic damage to your muscle fibers, which triggers the reparative process, termed muscle protein synthesis, in which the damaged fibers are repaired and built back stronger than before.
In order for this second step of the process—muscle protein synthesis to occur—your muscles need the proper environment or resources.
This is created by providing your body with protein, which can then be broken down to amino acids that are reconfigured to strengthen the muscle fibers, called myofibrils.
The increase in thickness in the myofibrils is what creates growth or an increase in the size of the muscle seen with hypertrophy.
In other words, rather than primarily being due to the growth of new muscle fibers, hypertrophy is due to an increase in the thickness of your existing muscle fibers.
Although muscle breakdown and muscle protein synthesis are ongoing processes, muscle growth occurs only when the rate of muscle protein synthesis exceeds the rate of muscle breakdown.
As mentioned, in order for muscle protein synthesis and repair to occur, the body needs energy in the form of calories as well as “building blocks” in the form of amino acids, which come from protein.
So, now we get to the question at hand: Can you build muscle in a calorie deficit?
There are two potential problems with being in a caloric deficit in terms of the adverse effects on muscle growth.
One, we just established: your body needs energy for the muscle protein synthesis process required to build muscle.
So, if you’re not taking in an adequate number of calories, this process is impeded.
Moreover, your body needs energy for all processes, including all the life-sustaining things that constitute your BMR (such as breathing and circulation) and all the physical activity and exercise you do.
Generally speaking, your body burns stored body fat and glycogen (stored carbohydrates) for the primary sources of fuel, depending on the intensity of the activity you are doing.
Protein is oxidized for fuel at higher intensities of exercise, but only about 10% of the energy comes from protein.
However, when you are in a fasted state or a caloric deficit, this percentage increases, meaning that more protein is being broken down to provide the calories/energy you need for your workout or whatever other processes your body is sustaining.
Unlike fat and carbohydrates, we don’t have storage forms of protein other than muscle tissue.
Therefore, when your body uses protein for energy, you break down muscle, which is the opposite of muscle building.
As can be seen, there’s a bit of a paradox in terms of building muscle in a caloric deficit.
In fact, most evidence suggests you need to be in a caloric surplus to build muscle.1Slater, G. J., Dieter, B. P., Marsh, D. J., Helms, E. R., Shaw, G., & Iraki, J. (2019). Is an Energy Surplus Required to Maximize Skeletal Muscle Hypertrophy Associated With Resistance Training. Frontiers in Nutrition, 6, 131. https://doi.org/10.3389/fnut.2019.00131
However, there’s an important caveat here. The concept of caloric surplus and deficit aren’t experienced by the body on this 24-hour clock we think of when we think about weight loss.
Rather, it’s minute by minute.
In other words, as soon as you eat, your body is in a state of caloric surplus because there’s an influx of energy and nutrients to use, and that influx probably exceeds what you can possibly use in the short time it takes you to eat the food.
When it’s been a while since you ate (such as when you first wake up), you’re in a relative caloric deficit.
This cycle continues throughout the day based on how many calories you’re eating and how often you eat.
At the end of the day, you might be in a net caloric deficit because you burned more calories than you ate overall, or you might be in a net caloric surplus, which means that you consumed more calories than you burned.
By strategically timing your nutrition to ensure you have enough energy, protein, and carbohydrates available during and after workouts, you can, in theory, still build muscle while in a net caloric deficit by the end of the day.
What Is a Caloric Deficit?
You’ve probably heard of the term caloric deficit before, but let’s look more closely at what that means.
When you are in a state of energy balance, the total number of calories you’re consuming through food and drink is equal to the total number of calories you’re burning in a day.
In other words, the “calories in” equal the “calories out.”
While it’s pretty straightforward to understand how to calculate the “calories in” side of things (so long as you measure portion sizes and look up the nutrition facts for everything you eat), the calories you burn in a day are more complicated.
Your total daily energy expenditure (TDEE) isn’t just the number of calories you burn during a workout; rather, it’s the sum of the calories you burn through four different factors:
- your basal metabolic rate (BMR)
- exercise
- non-exercise physical activity
- diet-induced thermogenesis (calories burned digesting food).
Unfortunately, it’s not that easy to accurately calculate the number of calories you burn in a day unless you go to a metabolic lab and get your BMR measured.
However, there are plenty of ways to estimate your BMR and overall caloric expenditure.
Wearing a heart rate monitor all day with a fitness watch that can estimate energy expenditure from heart rate is one of the most accurate ways, but you can also use an online calculator such as this one.
When you are in a caloric deficit, the calorie intake is lower than the number of calories you are burning, or, another way, you are eating fewer calories than you are burning in a day.
A caloric deficit is required for significant fat loss.
In general, a caloric deficit of 3,500 calories is necessary to lose one pound of fat.
How to Build Muscle and Lose Weight At the Same Time
Essentially, if you have enough calories, protein, and carbohydrates right after resistance weight training workouts, you can still build muscle even if your total caloric intake for the day is less than your energy expenditure.
Indeed, studies suggest that it is possible to build muscle in a caloric deficit so long as you perform resistance training programs that progress in load and volume while simultaneously following a high protein diet with frequent protein intake throughout the day.
Evidence suggests that the most effective diet to follow when trying to build muscle in a caloric deficit is to consume 2.3-3.1 g/kg of lean muscle mass per day of protein, 15-30% of your total calories from fat, and the remainder from carbs.2Helms, E. R., Aragon, A. A., & Fitschen, P. J. (2014). Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition, 11(1). https://doi.org/10.1186/1550-2783-11-20
Additionally, you should break up these nutrients into 3-6 meals per day, with the meal prior to and right after resistance training containing 0.4-0.5 grams of protein per kg of bodyweight.3Bj, S., & Aa, A. (2018, February 27). How Much Protein Can the Body Use in a Single Meal for Muscle-Building? Implications for Daily Protein Distribution. Journal of the International Society of Sports Nutrition. https://pubmed.ncbi.nlm.nih.gov/29497353/
Other studies have confirmed that you can build muscle in a caloric deficit if you consume a diet that provides 2.4g of protein per kg of body weight rather than one that provides just 1.2g of protein per kg of body weight.4Longland, T. M., Oikawa, S. Y., Mitchell, C. J., Devries, M. C., & Phillips, S. M. (2016). 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. The American Journal of Clinical Nutrition, 103(3), 738–746. https://doi.org/10.3945/ajcn.115.119339
For example, if you weigh 75 kg (165 pounds), you should consume 75 X 2.4g = 180g of protein per day and about 75 x 0.5 = 37.5g right after your workout.
Again, building muscle in a caloric deficit is all about getting enough protein and focusing on timing a large bolus of protein right after your hard strength training workout.
This gives you the stimulus (resistance training) and the environment and resources (protein and calories) needed for muscle protein synthesis.
Protein tends to get all the love when it comes to the nutrients people think they need to build muscle, but carbohydrates are also important.
Carbohydrates fuel high-intensity exercise, and if you recall back when your body doesn’t have adequate calories from stored glycogen (in the fasted state), the reliance on protein for energy, particularly during high-intensity exercise, increases significantly.
Therefore, it’s imperative to consume enough carbohydrates before and during your workouts to fuel your muscles with all the energy they need so that they aren’t turning to protein breakdown for fuel.
Typically, athletes need higher carbohydrate intake, but if you want to be in a caloric deficit, this isn’t always possible.
Aim for 4g/kg of body weight for the day, timing your carbohydrates to include a high-carbohydrate meal or snack before your workout, with carbohydrates in your post-workout snack as well.
If you weigh 75 kg, aim for 75 x 4g = 300 grams per day. It’s possible to go down to 3g/kg per day, but make sure you are focusing on partitioning enough carbohydrates right before your workout.
Finally, if you want to build muscle while in a caloric deficit, you need to keep the caloric deficit to a minimum so your rate of fat loss will be slower.
Research suggests a rate that doesn’t exceed 0.7% of body fat percentage per week.5Garthe, I., Raastad, T., Refsnes, P. E., Koivisto, A., & Sundgot-Borgen, J. (2011). Effect of Two Different Weight-Loss Rates on Body Composition and Strength and Power-Related Performance in Elite Athletes. International Journal of Sport Nutrition and Exercise Metabolism, 21(2), 97–104. https://doi.org/10.1123/ijsnem.21.2.97
If you weigh 75 kg, this works out to 75 x 0.007 = 0.525 kg or 1.2 pounds per week.
Final Thoughts
With a slow, steady, and strategic approach, it’s possible to build muscle and lose weight at the same time. Although there will likely be a sacrifice with muscle hypertrophy and lifters may also experience weight lifting performance losses.6Murphy, C., & Koehler, K. (2021). Energy Deficiency Impairs Resistance Training Gains in Lean Mass but not Strength: A Meta‐Analysis and Meta‐Regression. Scandinavian Journal of Medicine & Science in Sports, 32(1). https://doi.org/10.1111/sms.14075
If you need help working on on building body mass or losing fat mass, but don’t know where to start or which muscle groups to work, we recommend working with a personal trainer.
They can recommend the correct rep range or itnensity for you, whether it be squats or cardio!
If you are looking for macronutrient diet guidance to help with your muscle gain, check out our 7-Day Meal Plan For Muscle Gain.
