Lean body mass is a combination of low body fat and good muscle tone. So, lean body mass essentially includes the weight of your organs, skin, bones, body water, and muscle mass. All types of body fat are not included in the lean body mass. While ‘lean muscle’ is not a type of muscle, it is a phrase used to indicate your body’s weight minus all the fat mass. For this reason, lean body mass is also called fat-free mass.
Knowing your lean body mass helps you maintain optimum weight and keeps your body mass stable. So whether you are an athlete, sportsperson, or just trying to get healthy, it is essential to know your lean body mass.
How is Lean Body Mass Calculated?
While it is super easy to calculate your body weight using a weighing scale, calculating your lean body mass needs some more calculations. Lean body mass is the difference between your total body weight and total body fat weight. On average, healthy lean body mass value should be around 70% to 90%, and women tend to be on the lower end of this range.
There are many different ways to calculate your lean body mass– with some being basic and others more specific and accurate.
Using Your Height and Weight
This is the simplest way of measuring your lean body mass. This method uses a formula for men and women, and all you need to do is plug-in your body weight and height to get your lean body mass value.
Lean body mass= (0.32810 x Weight)+(0.33929 x Height)- 29.5336
Lean body mass= (0.29569 x Weight)+(0.41813 x Height)- 43.2933
However, this method is a crude way to determine your lean body mass and may not be accurate always.
Using Body Fat Percentage
This method uses a body composition monitor that accurately measures your body fat percentage. So, for example, if your body fat percentage is 30%, your lean body mass is 70%.
Using Other Parameters
By knowing your total body water %, bone mass, and muscle mass, you can calculate your lean body mass by adding these percentages together. Among these three parameters, your bone mass is not under your control, but the other two are. So, those who wish to reach a specific lean body mass % can work on the muscle mass and total body water percentages, both of which are possible with a good diet and the right physical activity.
There are a few advanced methods such as the skinfold assessment, bioelectrical impedance scale, and hydrostatic weighing that help in a more accurate assessment of lean body mass.
Why is Lean Body Mass Important for Athletes?
For any sports person or athlete, their performance is highly dependent upon their body’s composition because this directly affects their fitness and related parameters such as power, speed, agility, and balance. An athlete's skill and competency play an important role, but without the perfect body composition to support their activity, the individual will struggle to excel in his/her sport.
An increase in an individual’s lean body mass increases their strength and power, both of which are directly related to their muscle size. So, for an athlete, an increase in lean body mass helps them to generate more force for a specific time period. A higher percentage of lean body mass increases speed, agility, and quickness. Reduced body fat percentage contributes directly to an increase in respiratory, muscular, and cardiac endurance whereas, adding body fat can reduce the individual’s endurance, balance, movement, and agility. In fact, an increase in body fat also limits the range of movement of joints, thereby affecting the athletes’ coordination and movements. So, athletes and sportspersons who require agility, flexibility, and effective performance in their sport, must have low levels of body fat, i.e., a high percentage of lean body mass.
Based on the type of sport you play, the lean body mass, strength, and power ratios can be modified. For example, individuals who are participating in a sport that requires them to have more inertia and therefore need to maintain the right strength: mass ratio.
How Does Genetics Influence Lean Body Mass?
Lean body mass and muscle strength are both related to bone density, which has a strong genetic component. So, lean body mass is affected by a host of genes like ACVR2B, TRHR, FTO, and IRS1.
ACVR2B Gene and Lean Body Mass
Located on chromosome 3, ACVR2B gene codes for a receptor that is a negative regulator of skeletal muscle protein myostatin.
TRHR Gene and Lean Body Mass
The TRHR gene encodes the thyrotropin-releasing hormone receptor. This binds to the thyrotropin-releasing hormone. This coupling triggers a series of reactions that result in the release of TSH or Thyroid Stimulating Hormone and prolactin. The thyroid releases thyroxine in response to TSH and affects the skeletal muscle in humans.
rs16892496 is an SNP in the TRHR gene. Compared to subjects with the GT and TT genotypes, those with the GG genotype had 2.70 kg higher lean body mass.
Non-Genetic Factors that Influence Lean Body Mass
Apart from genetics, there are other factors that influence the development of lean body mass.
It is common to lose muscle mass and gain fat as we age past 30. If maintained with the right kind of exercise and physical activity, we can lose fat and prevent muscle loss.
Women tend to store more fat than men due to their bodies’ inherent needs. So, they are more likely to gain more fat and lose muscle mass, making it difficult to retain a lean body.
A decrease in estrogen levels decreases energy expenditure, which causes fat gain and lowers lean body mass. However, this factor is usually supplemented by a sedentary lifestyle or lack of activity.
Type of Activity
Performing aerobic activities causes increased fat burning, which helps increase lean body mass. However, if your caloric intake is high, but you are not burning enough calories with the activity you perform, your lean body mass will reduce, and the amount of fat stored in the body will increase. So, the type of activity you perform throughout the day directly influences your lean body mass.
Duration and Amount of Activity
Not just the type of activity but also its duration and amount make a difference to your lean body mass. If you exercise too much without the necessary caloric intake, you will end up losing not just fat but also muscle mass. So, how much activity you do for the nutritional intake matters if you wish to maintain a healthy lean body mass.
If your caloric intake is way too high compared to the calories burnt, the excess calories your body consumed will be stored as fat. Eating too few calories causes loss of fat as well as muscle mass. So, if you are looking to build optimum lean body mass, you must have a balanced nutritional intake that supports your endeavor.
Recommendations to Increase Lean Body Mass
The most important component of increasing your lean mass is exercise. However, you must also follow a few dietary and lifestyle recommendations to ensure you achieve your target lean body mass.
Without dietary and nutritional support for your workouts, increasing lean body mass is not possible. The main dietary goal while working to gain lean body mass is to increase your protein intake to allow your muscles to recover and grow after a workout.
Here are some foods that you must include in your diet:
- Greek yogurt
- Chicken breast
- Lean beef
- Soybeans and other soy products
- Cottage cheese
- Turkey breast
- Protein powders
- Nuts like almonds and peanuts
- Brown rice
With diet and exercise on point, some lifestyle changes help you get to your goal faster.
- Do not skip your breakfast, as it gives you the impetus to get going in the morning and sets the tone for the rest of your day
- Keep yourself hydrated at all times
- It is okay to consume carbs in your high-protein diet but make sure you don’t go overboard with calorie consumption. Consume half the quantity of carbs you usually consume and mix it up with low-calorie veggies to save up on caloric intake
- Though fats are needed by the body, you don’t want an excess of them while you are trying to cut down on them. Swap your high-fat meats with low-fat, lean meats
- Keep up your fiber intake as it reduces hunger, keeps you feeling full, and limits carbohydrate intake
- Train regularly and often
- Give yourself enough rest to allow your muscles to recover and grow
- One of the many fitness goals observed by people is to increase their lean body mass, which is different from weight loss.
- Lean body mass is essentially your body’s weight minus the weight of body fat.
Ideally, 70-90% of your body should be lean mass, with women being on the lower end of this range.
- There are different formulas and techniques to calculate your lean body mass accurately, and knowing this % is important for athletes and sportspersons.
- Reduced fat and increased lean body mass help athletes and sports person become stronger, leaner, more flexible, agile, and increase their movements and coordination.
- The amount of lean body mass that you inherently have or wish to build has a strong genetic component with genes like ACVR2B, TRHR, FTO, and IRS1.
- To achieve your target lean body mass goal, just working out is not sufficient. You need to have a healthy diet and nutrition plan that provides you with the right amounts of macronutrients, especially proteins.
- Certain lifestyle changes are also essential when you set out on a lean body mass journey.