We all want to achieve a lean and muscular physique. To do this, we obviously need to build muscle and burn fat. We’ve been told that it’s impossible to do both at the same time. ”You need to be in a calorie surplus!” But less is true. Trying to build muscle while losing fat is not impossible, but it may be less effective. You’ll read why in this article.
What happens in a calorie deficit?
When you’re in a calorie deficit, you’re consuming fewer calories than your body needs. This puts you into a catabolic state, your body is breaking down internal reserves for energy. The primary source our body taps into when it’s in a calorie deficit is body fat.
After all, our body gains fat (if you force it to), so it can use it in times of 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 increases.
As you’ve probably read in this post about protein intake, the human body builds muscle by building muscle proteins. This is often called: ”Protein Synthesis”. Our bodies also break down muscle proteins: ”Protein Breakdown”. If the number of muscle proteins your body builds exceeds the number of muscle proteins your body breaks down, you’ve built muscle.
So if you increase the number of muscle proteins you build and decrease the number of muscle proteins you breakdown, you will build 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.
But that’s not all, a calorie deficit also decreases anabolic hormone levels (like testosterone), which play a crucial role in the muscle-building process.
Is it possible to build muscle then?
This simply means that your body will build less muscle when you’re in a calorie deficit. But if it goes to the point where the number of muscle proteins you break down is greater than the number of muscle proteins you build, you will actually lose muscle.
For most people, this won’t be the case. We know through multiple studies that when inexperienced lifters train effectively, they gain muscle way faster than experienced lifters. So even if protein breakdown increases and protein synthesis decreases, they will still be able to build more muscle proteins than their body breaks down.
Even if the diet is super aggressive, we can see great results. If we look at a study by the University of McMaster, we can see that the inexperienced volunteers built 2 lbs of muscle and burned 10 lbs of fat while maintaining a calorie deficit of 40% in 4 weeks. So if you’re just starting off with training, you will build muscle. Yes, while losing fat! As long as your workouts are effective for stimulating muscle growth.
But this doesn’t change the fact that inexperienced lifters are able to build even more muscle if they’re not in a calorie deficit, because of all the disadvantages for muscle growth a calorie deficit brings.
The closer you are to your genetic limit, the harder it is to build muscle. Fitness researchers have put together guidelines to the amount of muscle you can build naturally overtime. Although they slightly disagree about how much muscle you can build naturally, they all agree that muscle growth significantly decreases as you get more advanced.
That’s why an experienced lifter may not be able to build muscle in a calorie deficit. The number of muscle proteins he/she will be building, won’t weigh off against the increased amount of muscle proteins he’ll be breaking down.
This is the main reason why advanced lifters go into ”bulking” phases and swear by them.
How most of us can build muscle and burn fat at the same time
Muscle growth is an adaptive response. By putting more tension on the muscle over time, it has to adapt. The human body does this by increasing muscle size and strength (a bigger muscle is a stronger muscle).
That’s why research shows that the key to muscle growth is progressive overload. You need to progress in the gym! There are several ways to do this. The most obvious way is by slowly increasing the amount of weight you’re lifting 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 nutrients to work with. From a short-term, ”muscle-building” point of view, this is true. But to burn a significant amount of fat you would need to stay in a deficit for a fairly long time (because you burn less fat on a small deficit). This is not favorable for several reasons.
But then again you gotta be careful, because an approach that’s too aggressive can decrease the amount of muscle you’re building. Based on these three studies, losing 0.5-1% of total bodyweight per week (basically 1-2 lbs per week) is recommended when wanting to improve body composition. This can be achieved by maintaining a calorie deficit of roughly 20-25%. Like in this study, in which athletes lost an average of 1.2 lbs per week by maintaining a deficit of 24%.
Research led by Eric Helms shows that protein requirements may increase as you restrict calories. Protein plays a vital role in muscle preservation when you’re in a calorie deficit. That’s why plenty of studies have shown that a high protein diet decreases muscle breakdown when you’re in a calorie deficit.
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 spectrum.
As you can see, building muscle and burning fat at the same time isn’t impossible. It just gets harder as you get closer to your genetic limit. As you advance, you might find that you’re not able to build a significant amount of muscle during your ”cut”.
The good news is that most people are far from close to their genetic limit and therefore will be able to effectively improve body composition.
If you are interested in learning more about maximizing your muscular potential, check out my new eBook “The Art & Science of Muscle Growth. This book translates the currently available scientific data about muscle growth in “Basic English”, so everyone can start implementing an evidence-based approach to training and nutrition.