Can You Build Muscle in a Calorie Deficit? 

If you’re looking to get in shape, your goals likely boil down to two objectives: losing fat and gaining muscle. Pulling off just one of them is no small feat. Knocking them out simultaneously—a process exercise scientists and fitness professionals call body recomposition—is tougher than explaining cryptocurrency to your grandma. 

The reason it’s hard to lose weight and gain muscle at the same time is that your body feels like it’s being asked to juggle two different jobs.  To lose fat, you need to burn more calories than you take in. To fuel muscle growth, you usually need to eat more calories than usual, especially protein. 

However, experts say you can build muscle in a calorie deficit—if you make the right tweaks to your routine. 

About the Experts

Avery Zenker, M.S., R.D., is a registered dietitian at Everflex Fitness. She holds a master’s degree in nutrition and specializes in sports nutrition and weight loss.  

Nate Osborne, CPFT-NESTA, is a personal trainer and the founder of Greatisfit Global Fitness.

Can You Build Muscle in a Calorie Deficit?

Building muscle while you’re cutting calories is possible, but experts say it’s easier for some people than others. 

If you’re new (or returning) to training, you’re at an advantage. When you start resistance training, your body builds muscle quickly, even in a calorie deficit. It’s not black magic: Because hefting weights is new to your muscles, it triggers a massive spike in muscle growth—the oft-mentioned newbie gains (1). 

Starting with a higher percentage of body fat can also help you build gains while eating less because your body burns stored fat to fuel your workouts. (2). 

What if you’re a seasoned lifter? You can still build muscle in a calorie deficit by dialing in on progressive overload and getting at least 2 grams of protein per kilogram of body weight, suggests a 2020 review (3). If you aren’t already meticulously managing your training routine and macros (which, we’d argue is most gymgoers), you’ll likely see changes by adjusting your approach.  

Just because you can build muscle in a calorie deficit doesn’t mean it’s ideal. A calorie surplus creates the perfect environment to maximize muscle gains, especially for experienced lifters who have less body fat to lose. 

While body recomposition is a solid goal, it typically isn’t sustainable long term. Once progress slows, switching to separate muscle-building and fat-loss (bulking and cutting) cycles might be the better route to progress on both fronts.

How to Build Muscle in a Calorie Deficit

To encourage muscle growth while eating less, experts suggest focusing on four specific things:

Keep your calorie deficit modest

Aim to cut anywhere from 10 to 20 percent of your calories, and no more than 500 calories a day, says registered dietitian Avery Zenker, M.S., R.D. 

“In a larger calorie deficit, the body can break down muscle to be used for energy, leading to decreased muscle mass. That can lead to feeling more fatigued and poorer recovery, which can make workouts more challenging and impede performance,” Zenker explains.

Research backs this up. One study found that elite athletes who reduced calories slightly built more muscle than those who drastically cut calories (4). Put simply, cut too many calories and you might spin your wheels and slow muscle growth. 

Get enough protein

If you don’t get enough protein in a calorie deficit, your body is more likely to break down muscle for energy, says Zenker. Eating enough protein helps offset the higher risk of muscle breakdown while you’re losing weight. 

The International Society of Sports Nutrition recommends consuming 1.4 to 2.0 grams per kilogram of body weight of protein per day to build and maintain muscle (5). “You’ll need more protein to build muscle when cutting calories,” explains certified personal trainer Nate Osbourne, CPFT-NESTA. In a calorie deficit, shoot for 1.8 to 2.7 grams of protein per kilogram per day—the higher your deficit, the more protein you’ll need (6). 

That doesn’t mean to neglect carbs. “Carbohydrates have a protein-sparing effect,” explains Zenker. If carbohydrates are sparse, your body may convert protein into glucose for energy through a process called gluconeogenesis. “When you eat enough carbohydrates it allows protein to be used for muscle building instead of energy,” she adds. 

Prioritize strength training

Strength training is a must. “Muscle is a use-it-or-lose-it deal,” says Osborne. Resistance training sends a potent signal to the body to increase muscle protein synthesis, even in a calorie deficit (7). Skip it, and you may find yourself losing muscle and fat (8). 

“As you cut calories, your athletic performance might drop,” says Osborne. Focus on efficient workouts, lifting close to failure with enough volume (sets and reps) for muscle growth. Aim for at least 10 working sets per muscle group a week.  

Emphasize recovery

Since cutting calories impairs your body’s ability to repair and build muscles after training, recovery is even more crucial during a calorie deficit. 

If you’re eating even a little less, you need to double your focus on sleep, stress management, and nutrition, explains Zenker. “These basic healthy habits help the body function at its best, keep energy levels up, and prevent you from feeling run down.” Recovery also supports immune function, which makes it less likely you’ll get sick and slow progress, she adds. 

A plethora of research suggests getting enough sleep, in particular, can help lock in gains. Why? The leading theory is that lack of sleep creates a catabolic environment, releasing hormones like cortisol that break down muscle tissue, and decreasing hormones like testosterone that build it (9). 

Sleep might also make sticking to a calorie deficit a little less of a nightmare. “Lack of sleep makes you crave food, so you might overeat,” says Osborne. Sleep loss tends to reduce satiety hormones (leptin) and increase hunger hormones (ghrelin) (10). Plus, there are simply more hours of the day you’re awake to eat. One review found that poor sleep was associated with bad snacking habits, including late-night cravings (11). 

FAQs

What happens if I lift weights in a calorie deficit?

Lifting weights in a calorie deficit is one of the most effective ways to build or retain lean muscle mass during weight loss. Research shows that resistance training, even on a very low-calorie diet, can help preserve muscle if combined with enough protein (12). 

Both cardio and resistance training have a potent effect on fat loss. However, resistance training has a better overall effect if gaining muscle and losing fat is your goal since it’s better for building muscle (13). 

Can you build muscle on 1,500 calories a day? 

Maybe, but probably not. “The amount of calories someone needs depends on a number of factors, like age, sex, physical activity level, body size, and health conditions,” says Zenker. “1,500 calories may be enough for someone with a smaller frame who is less active, but most adults need more than 1,500 calories per day to build muscle.” 

Does a calorie deficit burn muscle?

It can, but with the right approach, it doesn’t have to, says Zenker. Why is it so easy to lose muscle in a calorie deficit? Your body has less energy than it needs. Stored energy, from tissues like muscle and fat, is the easiest thing to break down since other energy stores are tapped out. 

If I’m losing fat-free mass am I losing muscle?

Fat-free mass includes mass mass, water weight, and glycogen. Typically initial loss isn’t muscle—water weight and glycogen come first—but it might register that way on simple body composition testing machines that only measure fat and fat-free mass.