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What is Lean body mass?

LBM is the difference between your total body weight and your body fat weight. It is also called fat-free mass or lean mass. LBM is composed of the following components:

  • Muscles are the tissues that contract and produce force and movement. Muscles are the main component of LBM and the most metabolically active tissue in the body.
  • Bones are the complex structures that support and protect the organs and provide muscle attachment points. Bones are also involved in mineral storage and blood cell production.
  • Organs: The vital structures that perform various bodily functions, such as the heart, lungs, liver, kidneys, brain, etc. Organs are essential for life and require a lot of energy to function.
  • Water is the liquid that fills the cells, tissues, and blood vessels. Water is involved in many processes in the body, such as temperature regulation, nutrient transport, waste removal, etc. Water makes up about 60% of the body weight of adults.
  • Other: The remaining substances that are not fat, such as glycogen, connective tissue, blood, skin, hair, nails, etc.

How do you Calculate Lean Body Mass?

Different methods exist to calculate LBM depending on the available data and equipment. The most common methods are:

  • Using body fat percentage: If you know your body fat percentage, you can easily calculate your LBM by subtracting your body fat from your total body weight. For example, if you weigh 70 kg and have 20% body fat, your LBM is 70 - (70 x 0.2) = 56 kg.
  • Using body measurements: If you don't know your body fat percentage, you can estimate it using some body measurements, such as your height, weight, neck, waist, and hip circumference. Various formulas use these measurements to calculate your body fat percentage and LBM. For example, the US Navy formula is:
    • For men: LBM = 1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)
    • For women: LBM = 1.29579 - 0.35004 x log10(waist + hip - neck) + 0.22100 x log10(height)

where LBM is in kilograms, waist, neck, and hip are in centimetres, and height is in meters.

  • Using bioelectrical impedance analysis (BIA): This device sends a small electric current through your body and measures the resistance or impedance. Since fat tissue has less water and more resistance than lean tissue, the device can estimate your body fat percentage and LBM. However, this method can be affected by factors such as hydration, food intake, skin temperature, etc.
  • Using dual-energy X-ray absorptiometry (DXA): This scan uses two low-energy X-ray beams to measure your body's bone mineral density, fat mass, and lean mass. This method is considered the most accurate and reliable, but it is expensive and requires a specialised machine and operator.

We have created a lean body mass calculator to calculate your LBM using any of these methods. All you need to do is enter your data and choose your preferred method.

Why is Lean Body Mass Important?

LBM is an important indicator of your health, fitness, and body composition. Here are some reasons why you should care about your LBM:

  • LBM reflects your muscle mass: Muscle mass is the primary component of LBM and the most metabolically active tissue in the body. More muscle mass equals greater strength, endurance, and power. It also implies having a higher basal metabolic rate (BMR), which is the number of calories you burn at rest. A higher BMR can help you stay healthy and avoid obesity and related disorders.
  • LBM affects your body fat percentage: The body fat percentage is the ratio of body fat to total body weight. It is a more accurate indicator of your body composition than your body mass index (BMI), which solely includes your weight and height. A low body fat percentage indicates a lower chance of acquiring cardiovascular disease, diabetes, hypertension, and some malignancies. LBM is the inverse of body fat; raising it can help you lose body fat and enhance your health.
  • LBM influences your physical appearance: LBM is also associated with physical appearance and attractiveness. Having more LBM means having a more toned, firm, and defined physique. It also includes having a smaller waist circumference, which is linked to a lower risk of metabolic syndrome and abdominal obesity. A greater LBM can help you reach your aesthetic goals while also increasing your self-confidence and self-esteem.

Related Tools

If you are interested in measuring and improving your LBM and body composition, you may also want to check out these related tools:

  • Body fat calculator: This tool can help you estimate your body fat percentage using various methods, such as the US Navy formula, the skinfold calliper method, the body mass index method, etc. You can also compare your results with the recommended ranges for your age and gender.
  • Weight calculator: This tool can help you convert between different units of weight, such as kilograms, grams, pounds, ounces, stones, etc. You can also use it to calculate your weight on other planets based on their gravity.
  • Ideal body weight calculator: This tool can help you find your perfect body weight based on height, gender, and body frame size. It can also show you the results of different formulas, such as Robinson, Miller, Devine, etc.
  • Ideal weight calculator: This tool can help you find your ideal weight based on age, gender, height, and current weight. It can also show you your target body mass index (BMI) and the healthy weight range for your height.
  • Lean body: This article can help you learn how to build skeletal muscle and achieve a slim body. It can also provide tips and exercises to increase your LBM and reduce body fat.
  • Army body fat calculator: This tool can help you calculate your body fat percentage and determine whether you meet the US Army standards of fitness and eligibility. It can also show you the maximum allowable body fat percentage for your age and gender.
  • Baby percentile calculator: This tool can help you track your baby's growth and development from birth to 2 years old. It can also show your baby's growth percentile and compare it with other babies of the same age and gender.
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