Can You Build Muscle In A Calorie Deficit? The Truth Revealed

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For many people, “losing weight” is a bit of a misnomer in terms of their actual fitness goal. In reality, in many cases, people that say they want to lose weight actually want to lose body fat and gain muscle.

These simultaneous body composition changes will have a more significant and dramatic effect on how your body looks and feels than just “losing weight,” particularly because losing weight can also involve losing actual muscle mass in addition to body fat if you’re not taking the right approach with your diet and exercise.

However, historically, when many fitness and nutrition professionals have been asked: can you build muscle in a calorie deficit, they have said that you can’t, meaning that you can’t build muscle and lose fat at the same time.

But is this true? Do you have to focus on just one body composition goal at a time, or can you build muscle in a caloric deficit?

In this article, we will look at if you can build muscle and lose fat at the same time and cover tips for getting the shredded body you’re striving for.

We will cover: 

  • What Is a Caloric Deficit?
  • Can You Build Muscle In A Calorie Deficit?
  • How to Build Muscle and Lose Weight At the Same Time

Let’s get started!

A muscular man getting ready to do a pull down at the gym.

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, and 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 number of calories you are burning in a day exceeds the number of calories you are consuming, or, said 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.

A nutritional label.

Can You Build Muscle In A Calorie Deficit?

Before we answer your questions, can you build muscle in a calorie deficit, let’s first see 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.

A trainer with a client at the gym, showing them they can build muscle.

Although muscle breakdown and muscle protein synthesis are ongoing processes, it’s only when the rate of muscle protein synthesis exceeds the rate of muscle breakdown that muscle growth occurs.

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.

A person doing a side lunge.

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.

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.

However, because the body works on more of an immediate time frame in terms of resource availability, if you are strategic about the timing of your nutrition such that you have ample energy, protein, and carbohydrates available during and after workouts for muscle protein synthesis, you can build muscle while being in a net caloric deficit at the end of the day. 

A muscular person drinks a protein shake at the gym.

How to Build Muscle and Lose Weight At the Same Time

Essentially, if you have enough calories, protein, and carbohydrates right after resistance 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 workouts 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 body mass per day of protein, 15-30% of your total calories from fat, and the remainder from carbohydrates. 

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 g/kg of body weight of protein.

A person with protein tubs on a table with a measuring tape around his bicep.

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.

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. 

A sign that says heathy carbs with a variety of carbs around it.

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 per week.

If you weigh 75 kg, this works out to 75 x 0.007 = 0.525 kg or 1.2 pounds per week.

With a slow, steady, and strategic approach, it’s possible to build muscle and lose weight at the same time.

If you are looking for diet guidance to help with your muscle gain, check out our 7-Day Meal Plan For Muscle Gain.

A person doing a renegade row.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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