Most of us want to achieve a lean and muscular physique. To do this, you obviously need to build muscle and lose fat. We’ve been told that it’s impossible to do both at the same time.
”You need to be in a calorie surplus to build muscle!”
Less is true. Building muscle in a calorie deficit is not impossible for most people. There’s also a good evidence base to support this.
But whether you can build muscle optimally while in a calorie deficit, well, that’s a different story.
What Happens In A Calorie Deficit?
When you’re in a calorie deficit, you’re consuming fewer calories than your body requires to fuel your daily activities. This puts you in a catabolic state, which means your body is breaking down internal reserves for energy. The primary energy reserve your body taps into when it’s in a calorie deficit is body fat.
After all, the body gains fat when you overeat so it can use the fat in times of food scarcity. But body fat is not the only thing your body breaks down when you’re in a calorie deficit. Research shows that muscle protein breakdown also significantly increases.
As you’ve probably read in my post about protein intake, the human body builds muscle by synthesizing new muscle proteins. This is referred to as ‘‘Muscle Protein Synthesis”. The body also breaks down muscle proteins: ‘‘Muscle Protein Breakdown”. If the number of muscle proteins your body synthesizes exceeds the number of muscle proteins your body breaks down, you’ve gained muscle.
So, if you increase the number of muscle proteins you build and decrease the number of muscle proteins you break down, you gain more muscle. Unfortunately, maintaining a calorie deficit does the exact the opposite. Research shows protein synthesis rates drop and protein breakdown rates increase when you’re consuming fewer calories than your body needs. So muscle growth essentially slows down when you are in a calorie deficit.
Calorie Deficit Slows Down Muscle Growth
But just because muscle growth slows down while in a deficit, doesn’t mean muscle growth is completely inhibited. With effective training and moderate calorie restriction, most novice to intermediate trainees can still gain some muscle. This is supported by several studies.
When it comes to overweight populations, they can even see good results if the diet is aggressive. In a 2016 study, overweight volunteers gained 2 lbs. of muscle and lost 10 lbs. of fat on average. They did this while maintaining a daily calorie deficit of 40% in a 4-week period. So if you’re not a seasoned lifter and have some body fat to lose, you likely will build muscle in a calorie deficit.
But let’s discuss the exceptions for a second. Because trying to build muscle and lose fat at the same time is not for everyone. Two factors seem to mostly influence how well (or not) you can gain muscle in a calorie deficit.
- Strength training experience
- Your body fat percentage
The leaner you are and/or the more experienced you are in strength training, the harder it becomes to gain muscle in a deficit.
Advanced and/or Lean Athletes
The closer you are to your “genetic limit” for muscle growth, the harder it is to gain muscle. So muscle growth naturally slows down as you advance in your training. As you can imagine, being in a calorie deficit will then only further slow down muscular adaptations. This is why a lean bulking phase is generally the way to go for experienced lifters that want to gain muscle.
With that said, this again doesn’t mean experienced lifters cannot build any muscle in a calorie deficit. It just means that if there is any gain in muscle size while dieting, it’s probably very slight. So slight that it may not be noticeable.
When it comes to lean athletes, by definition they have little body fat to lose. Because of the limited amount of stored energy available from fat tissue, you are likely going to break down more muscle proteins for energy. This makes you more susceptible to muscle loss and makes it unlikely that you can gain significant muscle while becoming even leaner.
Based on my experience coaching a wide spectrum of people, the trend I’ve noticed is that those who have 2+ years of effective strength training under their belt and/or are below 12% body fat (20% for females), have a hard time gaining significant muscle while losing fat.
But let’s not forget that most people out there are not very lean or advanced strength trainees. So the general population probably can lose fat and build muscle through effective training and nutrition.
How Most Can Build Muscle and Lose Fat
We now know that even though a calorie deficit is not optimal for muscle growth, most people still can gain muscle while in a deficit.
But in order to build muscle in a calorie deficit, you need to have a few key points in place. We’ll discuss these points below.
Muscle growth is an adaptive response. By constantly training your muscle beyond their present capacity, they’ll have to adapt. Your muscles adapt to overloading strength training by increasing muscle size and strength.
This helps explain why there’s research showing progressive muscle tension is an important mechanism for muscle growth. There are several ways you can progress in your training. The simplest way is increasing the amount of weight you lift or the number of repetitions you do with a certain weight over time.
When trying to build muscle, you’ll often hear that you need to maintain a small calorie deficit, so your body has more energy to work with. From a short-term, ”muscle-building” point of view, this is true. But to lose a significant amount of fat you would need to stay in a deficit for a fairly long time. This is not favorable for multiple reasons.
But then again you have to be careful because an approach that’s too aggressive can decrease the amount of muscle gain or preserve. Based on these three studies, losing 0.5-1% of total body weight per week is a good range for most people looking to improve body composition. This generally can be achieved by maintaining a calorie deficit of roughly 20-25%.
Protein plays an important role in muscle preservation when you’re in a calorie deficit. There are plenty of studies supporting this. Next to decreasing muscle breakdown, research shows that a high protein intake also increases the amount of fat you lose (in the same calorie deficit). So a high-protein intake helps with both sides of the equation.
A 2017 systematic review indicates that a daily protein intake of at least 0.7g/lb. (1.6g/kg) of body weight is sufficient for maximizing muscle growth. If you want to err on the safe side of things and want more of the satiety benefits of a high-protein diet, feel free to consume more protein in a day.
As you’ve read in this article, building muscle and losing fat at the same time isn’t impossible. It just gets harder as you get closer to your genetic limit and decrease your body fat percentage. If you have any questions about this article or have a question about your personal fitness, don’t hesitate to comment below!
Lastly, I want to finish off by mentioning my eBook that goes into how you can maximize your muscular potential. This book translates the currently available scientific research regarding muscle growth into “Simple English”, so everyone can start implementing an evidence-based approach to training and nutrition.
If you are interested in learning more about how to maximize muscle growth, check out my eBook “The Art & Science of Muscle Growth.”