Fat-free body weight: what is it and how to get there

Sabina Muminović Last updated: 27 October 2023

Is a fat-free body your ultimate workout goal? Do you spend large amounts of time sweating in the gym and lifting weights, all while keeping up with a strict diet?
If this is the case, you’re probably leaning towards a lean body!

Fat-free body weight refers to all of your body components except fat. It includes your body’s water, bone, organs and muscle mass. However, fat-free body mass refers primarily to muscle mass, which accounts for most of the body’s intracellular water mass.

Let’s see how we can calculate lean body mass, also called fat-free mass, its optimal percentage values, and how to increase its amount as much as possible.

In this article

Lean body mass
Healthy lean body mass percentage
Lean body mass calculation
The pros of having a lean body
How to increase lean body mass

Lean body mass

Okay, first things first!

You’ve probably noticed we use mass and weight here interchangeably. But, as you already know, mass is the amount of matter in a material, while weight is a measure of how the force of gravity acts upon that mass.

So, if you’re not satisfied with your weight, you should travel to the moon and see how you do there!

We’re kidding.

We know an easier way for you to reach a healthy weight. All you have to do is listen to your genes.

Promotional advertisement for Lifestyle DNA test

Discover your DNA and find out the optimal diet type, your response to carbohydrates and learn all about your genetic predispositions for sports performance. This way, you can eat and work out based on your genes. Besides that, you can even discover your lean body mass genetic potential!

But first, let’s have a look at the healthy lean body mass percentage.

Healthy lean body mass percentage

Lean body mass (LBM) is a part of our body’s composition. It’s the difference between total body mass and the mass of body fat weight. As we briefly mentioned, it counts the mass of all organs except body fat.

On average, a healthy lean body mass percentage depends mainly on age and sex. For men, healthy lean body mass ranges from 93 to 75 per cent of total body mass and for women, from 79 to 64 per cent. The reason why men have, in general, a higher proportion of LBM than women is due to significantly higher testosterone and oppositely lower oestrogen levels than women, responsible for increased muscle mass and, at the same time, decreased fat mass.

You can estimate your lean body mass with some easy formulas.

Lean body mass calculation

Several formulas have been calculating estimated LBM (eLBM), but we will show you the Boer one. It’s most commonly used and is said to be the most accurate one. To estimate your lean body mass, follow the formula below:

LBM (men) = 0.407 * weight [kg] + 0.267 * height [cm] – 19.2

LBM (women) = 0.252 * weight [kg] + 0.473 * height [cm] – 48.3

However, if you know your fat concentration, you can determine your exact LBM according to this simple formula:

Lean Body Mass = Body Weight – (Body Weight * Body Fat %)

You will need to:

• Measure your body weight,
• multiply your body weight by the fat percentage
• subtract the result from your body weight.

Of course, this is only an estimate! These easily accessible methods contain a fair amount of error.

It’s vital to note that your actual amount of muscle and fat may vary due to several factors such as exercise volume, dietary habits, physical health status, hormones, and your genes! 

Research has linked genetic variants within the TRHR, HSD17B11, VCAN, ADAMTSL3, IRS1, FTO, MC4R, and TNRC6B genes with lean body mass. Our Sport and recreation chapter of MyLifestyle DNA test can show you your potential for lean body mass, so you can find out how genetically inclined you are towards getting it and getting fit!

Besides that, it can help you find the perfect diet matched to your DNA. Is it low-fat? Balanced? Find out, avoid weight gain, master stress and sleep, boost your immune system and much more. 

The pros of having a lean body

Several people are now on a quest of having a significant percentage of lean body mass or as little fat as possible. Sure, this looks good, but it also has many other benefits! Let’s see what other benefits, beyond just looking fit, high percentage/proportion of lean body mass can bring to you:

1. Helps you battle disease

More lean body mass makes you less likely to become sick or develop health problems such as heart disease or diabetes.

Benefits of building lean body mass

2. It affects your metabolism and energy levels.

The more fat-free body mass you have, the higher your metabolism. The explanation for this is simple – muscles require energy in calories, while fat cells do not. So, the more lean body mass you have, the more calories you burn throughout the day, even when you rest!

3. Increases your strength and agility.

At around 30 years, our muscle mass typically begins to decrease. This results in a gradual loss of strength and mobility. But, we don’t lose our ability to rebuild or even build muscle mass from scratch! Strength training enables us to maintain or even gain lean muscle mass after the age of 30. This means we can remain mobile and strong for many years to come.

4. Contributes to strong bones.

The higher the lean body mass/body muscle mass, the higher the bone mineral density! The bigger and stronger our active muscles are, the more significant is the force on the bones. This forces the muscles to adapt and become stronger by having higher bone mineral density! Higher lean body mass also stabilizes and protects our joints while decreasing the likelihood of osteoporosis and osteoarthritis.

How to increase lean body mass

To the most important part: how can you reach a lean body?

Increasing your lean body mass is a two-factor equation: increase muscle mass and decrease body fat mass. Here are five easy ways to increase lean body mass.

1. Incorporate resistance training into your regular exercise routine.

To build more muscle, you must incorporate progressive resistance training, most commonly weightlifting or bodyweight training (callisthenics), into your training routine. As we mentioned, more muscular bodies burn more calories even while resting, and that’s crucial if you want to build lean body mass.

2. Eat protein!

The right amount of protein consumption helps increase and maintain lean body mass and has many other benefits, such as healthier hair and skin and building immunity. You can also benefit from protein intake during exercises, primarily if you work out for more extended periods and intense. When you consume a sports drink that combines carbohydrates with protein, your muscles will use the carbohydrates as fuel and protein as a signal to increase muscle protein synthesis (muscle building). To make sure you’re on the right path with your nutrition plan, use Food ID.

3. Recover.

You’ve probably heard this one before. Recovery is an essential part of your workout!
Training progress and building muscle happen only when regeneration surpasses the previous ability. This is called supercompensation.

Exercise increases your lean body mass, but it also increases the release of stress hormones. This, in turn, increases the muscle protein breakdown. If you want to minimise muscle protein breakdown, consume enough daily protein. Make sure to consume some protein after training and before you go to sleep (0,4g/kgBM/day) to increase the total muscle protein synthesis.

4. Get adequate amounts of sleep each night.

Sleep is crucial for increasing lean body mass. Try sleeping seven to eight and a half hours for multiple complete sleep cycles of REM. These cycles appear and repeat in approximately 90 minutes – during this time, most regeneration and adaptation occur. The more cycles you miss, the less recovery you will get. If this vital principle presents an obstacle for building a fat-free body mass, read this article about what to do if you can’t fall asleep.

Young woman sleeping in her bed

5. Be careful when dieting.

Dieting can help you get rid of unwanted body fat and increase lean body mass, but there is one crucial thing to note.

Extreme diets increase muscle protein breakdown. When you reduce your calories intake by 800–1000 calories, up to 45% of the weight loss could be your lean body mass! That’s why you should take a gradual approach to diet and slowly decrease your daily intake of calories for 300–400.

Besides watching your calories, you should also pay attention to increasing your fibre intake. Fibre is a type of carbohydrate the body can’t break down into glucose and use for energy. It makes you full for longer and slows the increase of blood glucose after a meal. Black beans, berries, sweet potatoes, and other high-fibre foods are digested at a much slower rate, causing a slow, steady stream of glucose into your bloodstream.

For great meal ideas which are simple to make, check out these recipes from our nutrition experts – they contain lots of protein and fibre to keep you on point in your lean body mass journey.

Eating healthily also doesn’t mean you should only eat fat-free food: these have less than 0.5 grams of fat per serving, while “low-fat” foods must have 3 grams of fat or less per serving. You should aim to keep your diet balanced, learn to listen to your body and see how it responds to different foods. However, to keep your heart healthy, the American Heart Association recommends limiting saturated and trans fats in your diet and eating healthier fats, sometimes called “good” fats. These include both monounsaturated and polyunsaturated fats, as they both lower the levels of LDL, or sometimes called “bad cholesterol” in your blood. Monounsaturated fats are found in canola and olive oil, while polyunsaturated fats are found in fatty fish such as tuna and salmon.

Of course, these are just general rules of thumb you should abide by. But there are no one-size-fits-all approaches or a diet that magically works for everyone.

A man lifting weights in a gym

To really learn how to get leaner, fitter, and improve your overall health, you should do a DNA test. It will help you discover your genetic predispositions for things such as your response to carbohydrates, fats, risk of becoming overweight, and even the diet type you should choose! You also get personalised recommendations to help you keep a healthy weight and improve your wellbeing – based on your DNA only.


• https://www.calculator.net/lean-body-mass-calculator.html
• https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/lean-body-mass
• https://www.healthline.com/health/benefits-testosterone
• https://inbodyusa.com/blogs/inbodyblog/52859201-why-building-lean-mass-is-important-for-everyone-even- you/
• https://www.calculator.net/lean-body-mass-calculator.html
• https://www.bodybuilding.com/fun/lbm_calculator.htm
• https://www.omnicalculator.com/health/lean-body-mass
• https://www.nutritionadvance.com/protein-health-benefits/
• https://www.bodybuilding.com/content/the-6-principles-of-getting-lean.html
• https://www.pacifichealthlabs.com/Five-Simple-Ways-to-Increase-Lean-Body-Mass-Overview_b_43.html

Share this article on