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Interviewed by AskMen on Caloric Deficit
How to Create a Calorie Deficit Without Losing Muscle
At the risk of stating the obvious: if you’re trying to lose weight, creating a calorie deficit — in other words, taking in fewer calories than you burn each day — is crucial. What’s not so obvious is figuring out how to create this deficit in a safe and healthy way, to ensure all your efforts don’t backfire. Consuming too few calories can seriously mess with your metabolism and compromise muscle tissue. So, is it possible to shed pounds without losing out on those hard-earned bis and tris?
The concept of a calorie deficit is pretty simple. If your body burns 2,300 calories in a day and you consume 1,800 calories, then you’ve created a 500 calorie deficit. But cutting calories alone without paying attention to the balance of macronutrients in your daily diet, or the type of training you’re doing on a weekly basis, probably won’t yield the results you’re looking for — and in fact, can lead to muscle loss. According to Nick Olsen, certified personal trainer and owner of x365 Fitness, this is because your body tends to metabolize muscle as a fuel source rather than fat when you’re not getting sufficient calories.
“This works against you in many ways,” he says. “The main way is that it lowers your resting metabolic rate (RMR). The more muscle you have, the higher your RMR is.”
In a 2011 study in the New England Journal of Medicine, overweight individuals were put on a diet of 550 calories per day for 10 weeks — and during this period of extreme calorie restriction, they demonstrated higher levels of the hormone that stimulates the appetite (ghrelin) and the hormone that promotes fat storage (gastric inhibitory polypeptide). Meanwhile, they also showed lower levels of the hormone leptin, which suppresses hunger and promotes fat burning, throughout the year following the study.
Creating a calorie deficit while maintaining or building muscle isn’t exactly easy — but it is possible. Here’s what certified trainers recommend.
Calculate Your BMR
In order to achieve a caloric deficit without compromising substantial muscle mass, you should start by finding out what an adequate caloric intake is for you, says personal trainer and former Olympian Ashley Kelly. You can do that by calculating your basal metabolic rate (BMR) using Kelly’s formula:
For an adult male: 66 + (6.3 x bodyweight in lb) + (12.9 x height in inches) – (6.8 x age in years) = BMR
For an adult female: 655 + (4..3 x weight in lb) + (4.7 x height in inches) – (4.7 x age in years) = BMR
Once you know your BMR, certified personal trainer and exercise physiologist Bianca Grover recommends multiplying your BMR by the appropriate factor based on your physical activity level:
If you are lightly active (light exercise/sports 1-3 days/week): BMR x 1.375
If you are moderately active (moderate exercise/sports 3-5 days/week): BMR x 1.55
If you are very active (hard exercise/sports 6-7 days a week): BMR x 1.725
If you are extra active (very hard exercise and demanding physical job): BMR x 1.9
From there, you can use an app like MyFitnessPal, Lose It!, or SparkPeople to log the number of calories you’re consuming and ensure you stay below your BMR.
Find the “Sweet Spot”
Once you know your BMR you’ll need to figure out your maintenance calories, says NASM-certified kuudose trainer Sean Crane. Your maintenance calories are the number of calories you need to consume per day to maintain your current weight. Next, take that number and multiply it by the percent deficit you’re aiming for. According to Olsen, a safe goal is a 20-25% daily calorie deficit. To get this number, multiply your maintenance calories by .20 or .25.
“At this rate, your body is comfortable and trusts you and won't start eating into your precious muscle tissue,” Olsen explains. “Try and wear a heart rate monitor for a full day and see how many calories you burn. Then, take 25% off that to get your daily caloric intake.”
For example, let’s say you need to consume 2,000 calories per day to maintain your current weight. Knowing 2,000 x .20 = 400, you’d subtract 400 from 2,000 to get your new daily caloric goal of 1,600.
“This is enough of a deficit to burn through body fat over time without losing weight drastically,” says Crane.
As a general rule, you should never go below 1,500 calories a day if you’re a man and 1,200 calories if you’re a woman, says Elliot Reimers, CISSN sports nutritionist and a NASM-certified nutrition coach at Rave Reviews.
Track Your Results
The human body is complicated — and no matter how many careful calculations you do, there’s no way to predict how your body will respond to dietary or activity changes. That’s why Michelle Wong, certified personal trainer and registered dietitian at Life Time, advises continually monitoring your results.
Everyone’s biochemistry is different,” she explains. “Measuring lean body mass and body fat percentage every couple of weeks and plotting the trend will show whether the right number of calories is being consumed, plus if they’re the right type of calories.”
Above all, notice how your body feels and performs, says Les Mills US trainer and studio manager James Thomas. Before making any adjustments to your calorie intake or training, he advises giving yourself two to three weeks to make observations about your progress.
Eat Smart
It’s not just how many calories you’re eating — it’s what you’re eating that matters.
“Muscles are comprised of water, protein, fat, and glycogen,” says Wong. “When exercise occurs, the muscle fibers break apart. Replenishment through food builds them back up, sometimes causing an increase in size through added protein filaments and other cells, or an increase in power through mitochondrial capacity.”
When you’re in a calorie deficit, ACE-certified personal trainer TJ Mentus recommends eating whole foods — including vegetables, fruits, whole grains, nuts and seeds, legumes, and fish — as much as possible. He also emphasizes the importance of staying hydrated, and filling gaps in your diet with the right supplement — like branch-chain amino acids (BCAAs).
“They’re low in calories and provide the building blocks for muscles that will help preserve them,” he tells AskMen. “These can be taken around workout times or during periods when you have gone a while without eating.”
NASM certified personal trainer Alex Robles, MD, says the best strategy to stick to is eating foods that are low in calories but high in satiating nutrients — so you can get the most bang for your buck, so to speak. For example, one 100-gram serving of raspberries only contains 52 calories but is packed with 6.5 grams of filling fiber. And a 3-ounce portion of shrimp contains a whopping 20 grams of protein with only 84 calories.
Get Enough Protein
The key to preserving muscle mass during a calorie deficit is making sure you’re eating plenty of protein.
In fact, a small 2016 study by McMaster University divided overweight young men into two groups — lower protein intake and higher protein intake — and then put them on a low-calorie diet and intense exercise regimen. After a month, those in the high-protein group lost more weight and body fat, as well as experienced greater muscle gains (about 2.5 pounds) compared to the low-protein group.
For men who want to maximize fat loss while maintaining muscle mass, Crane advises aiming for 1.2 - 1.6 grams of protein per pound. For example, if you weigh 180 pounds, multiply that by 1.2 and you should be trying to eat around 216 grams of protein daily. If you start to notice muscle loss you can increase your protein intake slightly within that recommended range. Someone who’s super physically active, for example, might need 1.6 grams of protein per pound of weight.
Try Carb Cycling
One popular technique for creating a calorie deficit is carb cycling, which entails alternating your carbohydrate intake on a daily or weekly basis. Essentially, you set a baseline level of protein and fat to consume every day and then switch between low, moderate, and high carb days.
“This keeps your body from going into starvation mode since some days it is getting more than enough calories on certain days and is never in a constant deficit,” explains Nolan Parker, NASM-certified personal trainer and CrossFit instructor, and product manager with TrueCoach. “I like to align my high carb days with the days that I perform hard workouts or am the most active. This helps ensure that the extra carbohydrates I’m consuming are stored as muscle glycogen.”
Remember: When carb cycling, you should only ever aim for a deficit of 250-500 calories below your total daily energy expenditure, says Parker.
Prioritize Resistance Training
Across the board, experts agree that regular exercise — specifically, resistance training — is imperative to preserving muscle tissue while you’re in a calorie deficit.
David Green, a certified personal trainer and co-founder at Aim Workout, recommends engaging in cardio training for about 150 minutes every week, strength training several days a week, and consistently increasing the intensity of your workouts (by adding weight, reps, etc.) over time.
“Make sure to hit 10-20 sets of 6-25 reps per week per body part using a range that brings you 1 or 2 reps short of failure,” says kuudose Celeb Trainer, Joey Thurman, CES CPT FNS. “Just make sure those last reps are creating a lot of mechanical tension or ‘muscular force’ to create change.”
According to Thomas, high-intensity interval training (HIIT) is also super effective for burning calories while limiting muscle loss.
“Unlike steady-state cardio, HIIT recruits more muscle fibers including your fast-twitch muscle fibers — so, overall you’ll find a greater calorie burn while maintaining, sometimes even gaining muscle mass.”
Keep in mind that there’s no one-size-fits-all approach to creating a calorie deficit while maintaining muscle, because the human body is complicated — your metabolism, hormones, stress levels, current body composition, and other health-related factors can come into play. As a result, Wong strongly recommends consulting with a registered dietitian and a certified fitness professional to devise a plan that works for you and your specific goals.
