Can You Gain Muscle in a Calorie Deficit? A Dietitian's Input
Can you gain muscle in a calorie deficit? When I ask my clients what their goals are, many report they want to “lose fat and gain muscle.” This big question is, can you do both at the same time? Here’s what you need to know.
What is a Calorie Deficit?
Simply put, a calorie deficit is defined as being in a state where you are burning more calories than you are consuming. For example, if you are burning 2,000 calories a day, but only consuming 1,500 calories, then you would be in what’s called a 500 calorie deficit.
Calorie deficits are primarily designed to deny the body of sufficient fuel via food in order to force your metabolism to burn its own fat reserves for energy.
How Does a Calorie Deficit Work?
The general guideline is that there are 3,500 calories in a pound of fat. So, theoretically, being in a 500 calorie deficit like we mentioned before should put one on track to lose a pound a week if you do the math. However, in practice, these numbers do not necessarily add up so neatly for linear and consistent weight loss. But that is the general rule of thumb.
One word of caution: I do not recommend being in a calorie deficit larger than 500 calories. My clients have a habit of believing more is better. “If 500 calories loses me 1 pound a week, then if I cut 1,000 calories I’ll be down 2 pounds a week!” The ambition is admirable, but this just isn’t safe as it likely won’t give the body enough fuel to perform its bodily processes in a healthy way.
Can You Be In A Caloric Deficit And Gain Muscle?
Losing body fat and building muscle is the dream of just about everyone who does resistance training. The thing is, you need to be in a caloric deficit to lose fat and you typically need to be in a caloric surplus (eating more than you are burning) in order to put on tissue (fat or muscle). So, what happens if you eat in a calorie deficit and lift weights? Can you be in a caloric deficit and gain muscle?
The answer is yes…and no. It’s complicated, but let me explain. The simple answer is that if you are an experienced weightlifter or trained athlete, it’s nearly impossible to gain muscle in a caloric deficit. However, if you are brand new to resistance training or only just began lifting weights the “right way” with the correct form, weights, and programming, then yes, you can gain muscle while in a caloric deficit.
The Science Behind Muscle Gain
In a study conducted by scientists at Gothenburg University, it was found that beginner weightlifters gained 4-7 pounds of muscle within the first three months of training. Assuming that they gained muscle at the same rate, this means they gained about 22 pounds on average. This is a massive amount of muscle!
This is why I advise my clients who have muscle gain goals and never tried resistance training before to take advantage of this time while they can. As you become more seasoned at training and these dramatic adaptations wear off, the magic is gone forever.
Once you reach this point, the body tends not to respond to a caloric deficit with muscle gain. Instead, if you aren’t careful, the body will begin to break down your muscle tissue for energy in a calorie deficit and nobody wants that.
What’s Most Important for Building and Keeping Muscle Mass?
The single most important thing you can do to gain muscle is to eat enough protein throughout the day. If you’re an experienced weightlifter just looking to lose some fat, then you need even more protein than someone who is trying to gain. Why? The body still needs amino acids to carry on bodily processes like making hormones and other non-muscle-gain-related things. So, like we talked about, the body can start to burn through your muscle in a calorie deficit if you don’t pay attention to your protein intake to get those amino acids.
However, studies have shown that if you give your body enough protein from your diet, your metabolism will burn through those amino acids instead of pulling from your muscle, thus conserving your hard earned muscle mass.
The Importance of Diet Quality and Muscle Gain
So, what if you’re a newbie or a more seasoned weightlifter who is just trying to make gains? Well, you still need to have a good balance of macronutrients, paying particular attention to protein and carbohydrates. It’s also super important that, if you’re in a surplus, to still be consuming healthy foods.
Many people see bulking up as an opportunity to eat high calorie foods with low nutritional value like pizza, donuts and ice cream. However, the body’s mechanism for putting on lean mass likely responds better to a diet of high nutritional quality. Generally, this diet would consistently include lean protein, healthy fats for extra calories, and plenty of fruits, vegetables, and complex carbs. This type of diet can also minimize the amount of fat you gain while following a bulking diet.
The Benefits of Weight Training for Muscle Gain
Finally and most importantly, make sure you lift weights! Or do some other form of resistance training. We can wax lyrical about diet all day long, but if you aren’t putting a progressive load on your muscles on a regular basis, gaining mass is going to be extremely difficult without resistance training.
Asking the body to put on muscle without an excess of calories to build new tissue from is like trying to defy science. However, there is a novel phenomenon called “newbie gains” that can make it happen for a period of time.
How Do I Get Started With a Calorie Deficit?
Unless you have some very fancy and expensive lab equipment laying around, though, there’s no practical and precise way to measure how many calories you are burning a day. Sure, your smart watches and cardio machines want you to believe they are telling you, but studies show these machines often overestimate your calorie burn by a large margin.
With so many moving parts and guesswork involved, let’s simplify it a little. If your goal is to get into a calorie deficit to lose fat while also minding your lean mass, to put on muscle mass as a resistance training newbie or just to put on muscle mass, there are four key things I recommend you focus on:
Calculate how many calories you are burning a day (also known as your TDEE, or total daily energy expenditure)
Set a diet plan that puts you in a caloric deficit based on your TDEE
Ensure this diet plan has the appropriate balance of macronutrients to lose fat, preserve muscle, and/or gain muscle
Have a solid resistance training program of the correct intensity, volume, and frequency to meet your goals
The Bottom Line on Gaining Muscle in a Calorie Deficit
As you can see, the question “Can you gain muscle in a calorie deficit” isn’t always a straightforward answer. This is why all of these things should be followed under the guidance of a nutrition professional if you want to do them correctly and safely.
As a personal trainer and registered dietitian who specializes in working with active populations, I’d love to show you the way. Check out my services to learn more.