How To Lose Fat Without Losing Muscle (Science Backed)

what you should do to lose fat without losing muscle

When looking to minimize muscle loss while dieting, it is key to cut calories slowly, lift hard with weights, and eat enough protein to support muscle retention.

In previous articles I’ve discussed topics like How Fast You Can Grow Muscle and How To Lose Fat Without Doing Cardio.

However, we have yet to specifically discuss what scientific studies have shown to be the most effective way to lose fat without losing muscle.

In this article we will review the science behind fat loss, muscle retention while dieting, and what you should do to lose fat without losing muscle:

  • Weight Loss vs Fat Loss – What’s the Difference?
  • How to Lose Fat without Losing Muscle – Scientific Review
  • How to Workout to Lose Fat Without Muscle Loss
  • How to Eat to Lose Fat Without Muscle Loss
  • How to Tell If You’re Losing Muscle and What to Do About It

Weight Loss vs Fat Loss: What You Need To Know

Often, these two terms are used intechangly, however they have very different meanings that should be clarified. 

The term “weight loss” simply refers to the amount of weight lost on a scale. 

For example, if you stepped on the scale today and weighed 200lbs, and in 10 weeks you weighed 190 lbs, you would have lost 10lbs of total weight over a period of 10 weeks.

But, what about fat loss?

When we look at our body weight (number on the scale), we do not get an accurate report on how much of that weight comes from our muscle tissue, fat mass, bones, water, and connective tissues.

Fat loss refers to the specific amount of weight lost that came directly from losing fat tissue.

So, in the example above, you may have lost 10lbs of weight, but what we found out is you lost five pounds of fat and five pounds of muscle (50% rate of muscle loss). That doesn’t sound very good, as building that muscle back will take you just as long as it took you to lose it.

When looking at losing fat without losing muscle, we need to monitor total weight loss, but also understand that only focusing just on how much weight is lost on the scale could, in the long run, have you losing just as much muscle as fat!

Let’s dive deeper into this topic and offer you some guidance on how to lose fat without losing muscle.


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Losing Fat Without Losing Muscle (6 Studies)

6 studies losing fat without losing muscle

Below are six studies that can help us provide more definitive guidelines on how to lose fat without losing muscle.

Study 1 – Fat Loss is 100% Dependent on Being in a Calorie Deficit and 100% Independent on the Method Used for Fat Loss

When it comes to fat loss, the most significant factor is that you are in a caloric deficit. 

Research has repeatedly shown that any combination of macronutrients can be an effective way to lose fat when calories are equated (1). 

This means that the biggest thing your diet needs to do is place you in a calorie deficit. We will discuss this further on how much or a deficit is effective for fat loss without losing muscle, and where those calorie cuts can come from to improve fat loss without losing muscle.

Study 2 – Excessive Cardio Can Interfere with Muscle Retention and Accelerate Muscle Loss While Dieting

Despite popular opinion, cardio (whether it is in the form of high intensity interval training, steady state cardio, or whatever cardio means) has not been proven to be a more effective way to lose fat than lifting weights if total calories burned is equated (2). 

When in a fat loss phase where you are concerned with not losing muscle, science has shown that excessive amounts or over-prioritization of cardio in an exercise program can interfere with the body’s ability to preserve lean muscle mass and even accelerate muscle loss.

Cardio should only be used as a third tool, behind being in a slight calorie deficit and lifting weights. 

Cardio can be helpful at times when it is easier to burn a few 100-200 more calories than it is to eat less, however, it should never replace lifting weights or interfere with weight training sessions. If cardio sessions are interfering or replacing weight sessions, then it is likely you are not losing fat due to not being in a caloric deficit.

Related Article:  Can Cardio Burn Muscle? (Yes, Here’s How)

Study 3 – Very Low Carb Diets Can Decrease Performance and Muscle Retention 

When looking to decrease calories to place yourself in a caloric deficit, it is important to understand the role carbohydrates play in optimizing performance during weight training sessions, muscle retention, and recovery.

Research shows that diets higher in carbs and lower in fat may be the better option for lifters and athletes who are looking to lose fat without losing muscle (3). 

This is because carbohydrates are the preferred fuel source for high intensity training (lifting weights) and the muscles store carbohydrates in the form of glycogen for energy. 

While you can still lose fat on a lower or no carb diet, you may find your weight training sessions will be impacted, especially if your training volume is high (which it should be).

Related Article: Can You Get Stronger Without A Caloric Surplus?

Study 4 – Lifting Weights Plays a Significant Role in Muscle Retention During Low Calorie Diets

Research has shown that during low calories diets, lifting weights is one of the most effective ways to retain muscle mass (4). 

When in a caloric deficit, the body often can shed muscle weight alongside fat weight, which can be remedied by lifting weights and making sure to expose the muscle tissues to heavier loads, lighter loads, and higher volumes of training.

Study 5 – Training with Heavier Loads Helps Retain Strength and Muscle Mass

Training with heavier loads (5-10 reps) is suggested for lifters and athletes who are looking to preserve as lean muscle and strength as possible during a fat loss phase. 

A meta-analysis of 17 peer-reviewed articles on the topic of weight training and weight loss, found that performing some movements in that rep range (they found 9-12 to be ideal) produced significant improvements in muscle and strength retention during weight loss periods (5).

Study 6 – Higher Rep Training Should Be Done to Failure to Be Effective

In addition to training with heavy loads in the 5-10 rep range, research has also shown that including higher rep training that is done to failure to be an effective stimulus for muscle growth.

This is a key finding since it suggests that you can lose fat and minimize muscle loss with both heavy and light weights, as long as the lighter weights are done to failure (6). 

It is important to note however that light weight training was not shown to have as much of an impact on strength retention, which is why for those lifters looking to lose fat without losing muscle AND retain as much strength as they can, a combination of heavy lifting and light lifting to failure is recommended.

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How To Workout To Lose Fat Without Muscle Loss

how to workout to lose fat without muscle loss

Below we will discuss ways to optimize your workouts to help you lose fat without losing muscle. Additionally, we will discuss some ways you can decrease strength loss during a weight loss phase.

Related Article: How Much Weight Can You Lose in 60 Days (The Healthy Way)

Still Lift Heavy to Preserve Muscle and Strength While Dieting

When trying to lose fat, you need to be in a caloric deficit, often for a prolonged period of time (6-12 weeks for most people). 

The longer you stay in a fat loss phase, the greater risk you run of losing muscle and strength, coupled with the less energy you will have to train hard. 

Generally speaking, a fat loss phase should not exceed 16-20 weeks, or a total weight loss of 10% of starting body weight.

It is important to lift weights, especially heavier loads (5-10 reps) throughout the fat loss phase to retain as much muscle as you can. This doesn’t mean you should only lift heavy weights, but rather that lifting heavy and light weights (not just light) should be part of your training program.

Related Article: How Much Weight Can You Lose in 60 Days (The Healthy Way)

Train Higher Volume to Preserve Lean Muscle Mass While Dieting

Training with lighter weights (10-15 reps & 15-25 reps) can be a very effective way to preserve muscle mass while dieting, especially when paired with heavy weights. 

While lifting heavy has its benefits, it does often increase fatigue, which can limit one’s ability to workout frequently or perform as much total work as possible. 

Since we know that total work (training volume) is one of the most important variables for muscle growth (and muscle retention), lifting with lighter weights can help you keep training volumes high despite low energy levels due to decreased caloric  intake.

For best results, train with both heavy and light weights, and be sure to train to failure with the lighter weights. Lifting to failure with heavy weights is not necessary to retain muscle and strength, since the loading is significantly higher than lighter weight sets.

Lifting Weights Should Be Your Primary Means of Exercise, Not Cardio 

When looking to lose fat without losing muscle, you need to make sure you are prioritizing weight training over cardio

Since you are in a calorie deficit, your body will lose weight, however if you are in a calorie deficit and lift weights, you will lose more fat and lose less muscle due to the established effects of weight training on muscle tissue.

If you are in a calorie deficit and primarily doing cardio, you WILL lose weight, however you will often lose more muscle than you would if you were to lift weights.

Use cardio as needed, but your main tactics for fat loss without losing muscle should be eating slightly less calories and lifting weights as frequently as possible.

On the Fitbod app, we can build workouts that match your specific goals and update your program each session based on the performance of prior workouts to truly optimize your training. Click HERE to get 3 free workouts.  

How To Eat To Lose Fat Without Muscle Loss 

how to eat to lose fat without muscle loss

Eating less calories than your body needs to maintain its normal activities will result in weight loss. 

When your goals are to lose fat without losing muscle, extra emphasis should be placed on the amount of calories you are in a deficit on a regular basis along with the individual foods you are cutting out to get there. 

In the below section we will discuss some of the biggest factors to help you eat in a more effective way to lose fat without losing muscle.

Related Article: How Long Does It Take To Get A Flat Stomach (Science-Backed)

Small Caloric Deficits Are Best to Lose Fat without Muscle Loss

When attempting to lose fat, many people are tempted to cut calories drastically to fast track their results. While this will certainly work for weight loss and biggest decreases on the scale, it often is due to higher proportions of muscle being lost.

It is recommended that you aim to lose 0.5 to 1.0 lbs of total body weight per week during a diet phase, as any faster than that and it suggests you are losing muscle tissue. While you may be tempted to push for 1.5lbs or more loss per week, it often comes at the cost of losing muscle. 

For best results, start by dropping calories per day by 200-300 in the first week, and monitor overall weight loss. 

If you find you are losing weight within the acceptable range, hold your calories there and repeat for another week. 

If you are not losing weight or your progress plateaus, drop another 200-300 calories and repeat this weekly check in until you have reached your goals or until your calories drop below 8-10 calories per pound, per day. 

If you are eating less than that, you need to focus on working out more, increasing activity levels, increasing your metabolism through exercise rather than starving yourself.

Higher Protein Diets Can Help Preserve Muscle During Weight Loss

Diets higher in protein can be a very effective way to preserve muscle mass and recovery from hard, high volume training sessions. 

During a fat loss phase, the need for protein is often more than you would consume when not in a calorie deficit and is suggested to maintain muscle mass.

Most individuals should aim to consume at least 0.8-1.0 grams of protein per pound of bodyweight, with slightly higher amounts (1.0-1.2 grams) to be ideal, especially for more advanced lifters or individuals who train hard.

Cutting Carbs in Your Diet May Impair Your Ability to Train Hard

Carbohydrates play a critical role in muscle growth, performance, and recovery. Diets lower in carbs or ones that restrict carbohydrate intake altogether have been shown to be an ineffective way of increasing muscle retention and performance during a fat loss phase. 

While diets high in fat and low in carbs can result in fat loss, and even provide you with energy to workout, research has shown that it is not the most optimal way to lose fat without losing muscle. 

The most optimal form of energy for muscles, especially during weight training and hard workouts, is glucose, which is most easily available via carbohydrates in the diet and muscle tissue (stored as glycogen).


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How To Tell If You’re Losing Muscle & What To Do About It

how to tell if you’re losing muscle and what to do about it

Chances are during the fat loss phase you will “feel” like you are losing muscle. And to be honest, you most likely will lose a little bit of muscle.

If you suspect you are losing muscle, or are curious how to determine if you are and at what rate, you can start by making sure you are addressing the variables below that will correlate with losing muscle during a fat loss phase.

Losing Weight TOO Fast

We discussed the pitfalls of crash dieting and the rate at which you should aim to lose weight when looking to lose fat without losing muscle. 

The number one reason people lose muscle during a diet is losing weight too fast. The second reason is not lifting weights enough (see below).

Stick to losing 0.5-1.0lbs per week. If you are leaner or more advanced, and have less fat to lose, stick to the lower end for best results, as more scale weight loss is not always the best way to lose fat and retain as much muscle as possible for more advanced individuals.

Not Lifting Weights As Frequently

If you are fearing that you are losing muscle, then train more frequently. This will allow you to keep the muscle building stimulus on the muscle groups that you are concerned about AND increase caloric expenditure. 

For example, if you train muscles once a week (3 days a week workout program) during a diet phase and are thinking you are losing muscle, step your workouts up to 4-5 days a week. 

It’s a short amount of time to carve out more gym time, but will be worth it in the end. Ideally, you would train most muscle groups 2-3 times a week to optimize muscle retention during a fat loss diet.

Not Training To Failure

As discussed above, if you are training with lighter loads, it is imperative that you train to failure, and accumulate a ton of volume and stimulus to the muscles. 

If you are training the muscle to near failure, and getting a ton of muscle fatigue and feeling the muscle “burn”, there is a good chance you are providing enough stimulus to signal muscle retention. 

Again, make sure you are not lifting too light though, as a combination of heavy, moderate, and light weight training is probably best. Note, if you are training heavy, training to fatigue is not necessary. We discussed this in the above sections.

Not Tracking Body Fat

This can be done using calipers or even body scans, and while it may not be the most accurate measure, you can at least use the same device throughout the fat loss period to come up with a reliable way to measure your change from beginning to end. 

Doing the math and calculating your fat free mass, fat mass, and percentage of loss based on your measurements can offer you some quantitative data to go off of and help you keep a clear mind during your diet.

Final Thoughts

Losing fat without losing muscle is very doable, and has been done by many beginners and high level lifters and athletes. The key is to follow a sound diet plan that emphasizes slower rates of weight loss, while also training with weights on a frequent basis. For best results, be sure to track your rate of weight loss, body fat percentage, and train hard!

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About The Author

Mike Dewar

Mike holds a Master’s in Exercise Physiology and a Bachelor’s in Exercise Science. He’s a Certified Strength and Conditioning Specialist (CSCS), USA Weightlifting Advanced Coach, and has over 10+ years of experience working with collegiate athletes, national level lifters, and beginners alike. Mike is Founder of J2FIT Strength and Conditioning, a growing global training company with gyms in New York City, Cincinnati, and online offering personal training, online custom coaching programs.

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  1. Kiens, B., & Astrup, A. (2015). Ketogenic diets for fat loss and exercise performance. Exercise and Sport Sciences Reviews, 43(3), 109. https://doi.org/10.1249/jes.0000000000000053 
  1. Ardavani, A., Aziz, H., Smith, K., Atherton, P. J., Phillips, B. E., & Idris, I. (2020). The effects of very low energy diets and low energy diets with exercise training on skeletal muscle mass: A narrative review. Advances in Therapy, 38(1), 149–163. https://doi.org/10.1007/s12325-020-01562-0 
  1. Filho, S. (2014). STRENGTH TRAINING AND VOLUME OF REPS FOR WEIGHT LOSS: A SYSTEMATIC REVIEW. Revista Brasileira de Ciências da Saúde. Retrieved September 17, 2021, from https://cdof.com.br/ARTIGOS/Silva%20Filho%20et%20al.,%20(2014)%20Treino%20de%20for%E7a%20e%20o%20n%FAmero%20de%20 repeti%E7%F5es%20INGLES%20(COBEC).pdf. 
  1. Schoenfeld, B. J., Peterson, M. D., Ogborn, D., Contreras, B., & Sonmez, G. T. (2015). Effects of low- vs. high-load resistance training on muscle strength and hypertrophy in well-trained men. Journal of Strength and Conditioning Research, 29(10), 2954–2963. https://doi.org/10.1519/jsc.0000000000000958