Calorie Deficit Without Losing Muscle (Easy guide)

Studies show that people who fail to maintain their lean body mass during dieting are more likely to regain all the weight that they’ve lost. Today I will explain if calorie deficit leads to muscle loss, and if so, how can you prevent muscle loss while dieting?

As a whole, prolonged calorie deficit without adequate protein intake does lead to muscle loss, as well as impaired muscle function. However, high protein intake (around 2.0 to 2.4 g of proteins per kg of body weight per day) helps preserve the lean body and muscle mass during weight loss.

Does Calorie Deficit Lose Muscle?

Building muscle when you eat a lot is fun because you can eat what you want and you have tons of energy to really push it on your training days. But during a calorie deficit, building or maintaining muscle mass is a totally different level.

Does calorie deficit lose muscle? In general, calorie deficit does lead to loss of lean body (including muscle mass) because of reduced muscle protein synthesis and increased breakdown. Studies show that people who lose weight without eating enough proteins, lose their muscle mass (with 58% of weight loss coming from lean body mass).

Here is a good study that illustrates how important is protein intake in preserving muscle mass.

Dr.Stefan M Pasiakos from the United States Army Research Institute documented and compared 12 people who were divided into two 10-day periods and assessed the protein intake in either calorie deficit or calorie maintenance.

  • In the first 10-days, all participants were dieting (20% of calorie restriction) and eating around 1.5 grams of protein per kg per day.
  • During the second 10-days, all participants weren’t dieting anymore, but still ate the same 1.5 grams of protein per kg per day at their “maintenance” calorie level.
Calorie deficitCalorie maintenance
10 days 10 days
106 g protein106 g protein
272 g of carbs367 g of carbs
72 g of fat86 g of fat
Total: 2,162 kcalTotal: 2,684 kcal

As you can see, the amount of protein was the same in both trials, but the total amount of total calories differ by around 500 kcal.

  • During the calorie deficit phase, participants ate around 2,162 kcal, and 2,684 kcal in the maintenance phase.
  • The goal was to assess the difference in muscle protein synthesis and muscle protein breakdown activity during both of those phases.

NOTE: Please remember that 1.5 g of protein per kg is around twice as much as the current RDA (recommended daily allowance).

The results showed that during the calorie deficit phase, the muscle protein synthesis was 19% lower, compared to the maintenance phase (source).

Why You Lose Muscle When Doing Calorie Deficit?

In general, during a calorie deficit, the muscle protein breakdown increases, and muscle protein synthesis goes down, which leads to muscle loss. In order to preserve muscle mass in the calorie deficit, you need to eat more proteins than during the maintenance calorie intake.

Preserving your muscle while you’re in a deficit will not only make you look diced and saucy but also ensure you won’t regain all the weight that you lost.

I won’t be covering here the mechanism behind how much protein should you eat during the calorie deficit. I’ve already covered that in my article “calorie deficit and protein“, which I recommend you read.

In short, for optimal muscle protein synthesis during the calorie restriction, you need around 2.0 – 2.4 g of protein per kg per day (source).

However, high protein intake alone won’t be enough to fully prevent muscle loss. You also need strength training, progressive overload, and optimal sleep (more on that later).

How To Prevent Muscle Loss During Calorie Deficit

Generally, you can prevent muscle loss in a calorie deficit by eating between 2.0 to 2.4 g of proteins per kg per day, reducing excessive cardio workouts, prioritizing HIIT training, strength training with progressive overload, reducing stress, and implementing more restful sleep.

So sit tight, and make yourself a cup of coffee because here are the 6 proven ways to prevent muscle loss in a calorie deficit.

#1 Increase Your Protein Intake

Overall, to do calorie deficit without muscle loss you need to increase your protein intake to around 2.0 – 2.4 grams per kg. During the calorie deficit, the amount of protein required to maintain muscle mass goes up.

Muscle turnover is a dynamic process that can be compared to plasticine, or even chewing gum. In the most simplistic way, our muscles are plastic and respond to different signals to either grow or shrink.

Those signals can be divided into muscle protein synthesis and muscle protein breakdown.

What is muscle protein synthesis? Muscle protein synthesis (MPS) is a process of remodeling and building muscle mass. It is triggered by the sufficient availability of amino acids in the body and muscle damage (from exercise).

When you do a biceps curl, your muscle will adapt and grow. When you add more weight, your muscle will adapt again, and grow more.

What is muscle protein breakdown? Muscle protein breakdown (MPB) is also part of muscle remodeling but in the opposite way. It catabolizes the muscle tissue when there are not enough amino acids available in the body.

When you stop doing biceps curl, your muscle will adapt again, and shrink.

Here’s the kicker.

In the state of calorie “maintenance”, which is when our calories that come in matches calories that go out (we don’t gain weight and we don’t lose weight) our muscles are happy with just the “regular” protein intake to keep doing their job.

#2 Start Doing Strength Training

In general, to prevent muscle loss on a calorie deficit you need regular strength training with sufficient workload and intensity at 70-90% of 1RM. Higher the load (weight) not only triggers a higher response in muscle protein synthesis but the response in itself is elevated for much longer.

This means doing a light set of curls on Bosu ball or walking on the elliptical is not gonna cut it. You need something more than that.

Let me explain.

What is intensity? In resistance training, intensity is basically how heavy you can lift. And to be more specific, intensity can be measured by the percentage of your 1RM (one rep max).

Let’s take a leg press as an example. If you can load leg press to do 200 lbs for one rep only, that is your 1RM


  • 20% of your one reps max will have a minimum intensity, and therefore, doesn’t trigger enough response in the muscle protein synthesis.

So if you are doing a leg press with 20% of your 1RM (40 lbs) it is ok for general mobility, but it is not enough to trigger MPS.

  • 75% of your one reps max have a significantly higher intensity and lead to a huge spike in MPS. Do going with heavier lifts and lower reps will is much more efficient.

So if you keep on doing your leg press with 150 lbs for a number of reps, this will have a massive effect.

A study was done by Dr. Vinod Kumar from the University of Nottingham in the UK, and compared a group of 25 healthy men and the impact of different intensities on muscle protein synthesis.

From the Dr. Vinod Kumar study, I’ve pulled a table where you can see a comparison of different intensities of strength training and the impact on muscle protein synthesis (source).

IntensityIncrease in MPS
None baseline level
20% 1RM+20%
40% 1RM+25%
60% 1RM+125%
75% 1RM+177%
90% 1RM+137%

As you can see from the graph, the biggest effect on muscle stimulus had 75% of 1RM, and intensities greater than 60% of 1RM increase muscle protein synthesis 2x to 3x fold.

How often should you be doing resistance training? If you do 60-90% 1RM intensity, you should aim for around 3-4 times per week.

Are there any specific exercises to help with muscle loss in a calorie deficit? The most effective will be big, compound lifts because you can add more weight and engage more muscle at the same time.

Doing multi-joint movements not only will trigger greater MPS, but also burn more calories as they will elevate energy expenditure for much longer, compared to single-joint exercises.

Here are some of the most effective compound movements that help to prevent muscle loss during a calorie deficit.

Bench press
Lat pull-down
Shoulder press
Exercises that prevent muscle loss during a calorie deficit

You can lift more weight, and engage more muscles when doing leg press, comparing to lex extension.

#3 Add Progressive Overload

Once you have your protein dialed in and you are doing your resistance training, the next step is to add progressive overload.

Overall, you can do calorie deficit without losing muscle by implementing resistance training with progressive overload. Progressive overload means increasing your training volume (lifting heavier weights, doing more reps/sets, and/or doing more exercises per session).

This strategy not only will help you to prevent muscle loss during the deficit, but also give you better weight loss results.

NOTE: Just remember that there are several ways to implement progressive overload, and it doesn’t always mean more weight.

Here are some of the examples:

Progressive overloadHow it works
More repsLifting the same weight but adding more repetitions over time
More setsLifting the same weight but adding more sets over time
Better formLifting the same weight but doing so with less effort and more control
More time under tensionLifting the same weight but slowing down during the lift
More volumeLifting the same weight but doing more training sessions in a week
More distanceCarrying weight for longer or further
Super setsLifting the same weight and adding additional exercise back to back
More timeAdding more time to the overall session
Less timeReducing session time but keeping the intensity higher
Progressive overload variations to prevent muscle loss

The purpose of adding a progressive overload component to the workout is to avoid the plateau.

If you train with the same intensity for several months or even years, initially it will stimulate the muscle to grow. But sooner or later, you will hit the plateau, and the growth will plummet.

It’s kind of like playing tennis or a video game with the same people and winning every match with no effort. To get better, and to progress, you need to challenge yourself.

Apart from muscle changes, when you add progressive overload during your calorie deficit, it will help you burn more calories, and maintain your metabolic rate.

#4 Reduce Excess Amount Of Cardio

As a whole, you can do calorie deficit without muscle loss by reducing the amount of cardio because it can accelerate muscle protein breakdown. Studies have shown that cardio is effective in burning calories. However, people who do more strength training tend to keep their metabolic rate higher and maintain more muscle mass.

Of course, cardio is an essential tool to improve your cardiorespiratory fitness. Plus, it also has several other physiological and psychological benefits.

Cardio is been the most popular training choice for decades. However, if you’re in a deficit, and your goal is to prevent muscle loss, you should reconsider reducing the volume of aerobic training.

Research shows that when you do any form of cardio like running, swimming, or cycling you burn tons of calories, but what about muscle mass?

A study done by Dr.A Geliebter from the Columbia University College of Physicians and Surgeons in New York compared 65 people and divided them into three separate groups.

Group 1Diet + strength training
Group 2Diet + aerobic training
Group 3Diet alone

The diet + strength group was instructed to perform resistance training together with a calorie restriction plan.

The diet + aerobic group was instructed to do cardio sessions along with dieting.

The Diet group was doing the diet alone.

The complete trial took 8 weeks, and the goal of this study was to assess the difference between all three groups in the body composition, lean body mass, and fat mass.

NOTE: All people received a diet with a steep calorie deficit (1300 kcal per day) which was around 70% of their BMR.

Here are some details of this study.

ProtocolAerobic groupStrength group
Volume3 x week3 x week
Duration30 min60 min
TypeArm and leg cyclingFull body workout
Work intensity70% max heart rateno details

The results? All groups experienced huge weight loss within just 8 weeks. However, there were some differences in the body composition (source).

In general, diet alone managed to lose the most amount of weight, however, they also lost the most amount of muscle mass.

The diet + strength group lost the least amount of weight, but they preserved the most muscle. The diet + aerobic group lost the most amount of fat, but they also lowered their metabolism by over 600 kcal.

Here are the details.

D + SD + ADiet
Total–7.8 kg–9.6 kg–9.7 kg
Muscle –1.1 kg –2.3 kg –2.7 kg
Fat–6.7 kg –7.2 kg –6.8 kg
Metabolic rate–532–623–369

As you can see, the results are mixed. This basically means that each form of exercise has its advantages and disadvantages. A great alternative for cardio is doing HIIT (high-intensity interval training).

#5 Do High-Intensity Interval Training

High-intensity interval training is a perfect and time-efficient alternative to aerobic training. It’s short, intense, and gets you out of breath every time.

In fact, some studies suggest that HIIT is similarly effective in triggering muscle protein synthesis as resistance training for certain populations (post-injury or older people) (source).

How does HIIT work? HIIT is basically high volume short bouts of exercise at or above maximal aerobic capacity. This means you are getting smoked with a single movement (or set of exercises) with minimum rest.

If you ever done burpees back to back you know what I mean.

In a study done by Dr.Katie R. Hirsch from the University of North Carolina, they’ve documented 66 adults undergoing mixed HIIT training.

The groups was divided further into 4 sub-groups:

HIITDoing high-intensity interval training 2x week
HIIT + EAADoing high-intensity interval training 2x week and taking supplementation of essential amino acids (3.6 g twice per day)
EAA (no training)Taking supplementation of essential amino acids (3.6 g twice per day), without any workouts
ControlNo instructions

The study took 8 weeks and all people were measured at the beginning and at the end.

Here are some of the details of the protocols.

EquipmentCycle ergometer
Duration12-20 minutes
Work intensity60 seconds (90% max)
Rest60 seconds (complete rest)
Number of sets6-10

Both groups, HIIT and HIIT + EAA went on the same interval training.

During the 8 weeks, all participants applied the progressive overload principle for the first 5 weeks with sets gradually increasing each week.

From the fifth week, progression plateau at 10 sets per session.

The goal of this study was to see how effective was high-intensity interval training in the prevention of muscle loss.

The results? The highest protein synthesis was measured with groups HIIT + EAA and EAA alone. Interestingly, the HIIT group experienced a decrease in protein synthesis.

NOTE: This shows that doing HIIT without being mindful about protein intake won’t increase lean body mass. The best way to prevent muscle loss is to combine HIIT with an adequate amount of protein.

To learn more about how to create your own HIIT workouts check out my article about doing kettlebell swings and conditioning.

#6 Add More Restful Sleep

Sleeping more sounds like super basic advice. However, every time when I explain the importance of sleep to my clients, I see jaw drops and eyes stare.


Because all it takes is one single night of sleep deprivation to down-regulate muscle protein metabolism.

Let me show you what I mean.

In the famous study done by Dr.Séverine Lamon from the Deakin University in Australia, they took 13 people divided them into two subgroups, sleep-deprived group, and normal sleep group.

The study was relatively short because it only took one night.

NOTE: It is actually unethical to conduct long-term sleep deprivation studies. That’s why most of the research is done on the max few days of trials.

The results? The results showed that just one single night of sleep deprivation was enough to reduce muscle protein synthesis by 18%.

Also, in the sleep-deprived group levels of testosterone decreased by whooping by 24%, and the stress hormone cortisol increased by 21%.

Here are the details.

Normal sleepDeprived sleep
Protein synthesisbaseline–18%
Cortisol (stress)baseline+21%

As you can see, sleep can be really underestimated. Sometimes we can have everything right with our proteins and training.

We can do all types of magic, drink extra EAA, drink intra-workout drinks to enhance recovery, and optimize our workouts with progressive overload.

But when sleep is out of wack, no amount of protein or gym training will prevent from losing muscle.

Keep that in mind.


In summary, there are multiple dynamic factors that can cause muscle loss during the calorie deficit. The optimal amount of protein should be around 2.0–2.4 g per kg per day to ensure we have enough amino acids available in the tank.

Also, adequate resistance training with progressive overload plays an important role to maintain muscle mass and preventing muscle protein breakdown.

Finally, lifestyle aspects like stress and sleep are equally important to maintain lean body mass while doing a calorie deficit.

Michal Sieroslawski

Michal is an exercise physiologist (MSc) and a veteran endurance athlete. He loves to experiment and share his successes and failures to help busy men and women who want to lose weight.

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