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What is Lean Muscle?

Kelly Ferguson
Kelly Ferguson

Fitness professionals generally describe body composition in terms of two categories: fat body mass and lean body mass. Fat body mass includes all of the body’s fatty tissue, while lean body mass includes everything else, such as the bones, organs, and muscles. Therefore, the term lean muscle refers to the fact that muscle is part of lean body mass. These two components are usually measured in a ratio, or by percentage. Body fat percentage, the amount of the body composed of fat mass, is becoming an increasingly popular way to measure fitness levels.

In previous decades, an individual was generally judged to be overweight or underweight based on how much that person weighed in relation to his or her height. The medical community still uses a measurement called body mass index (BMI) to evaluate a person’s weight and determine if he or she is healthy, or needs to gain or lose weight. BMI is based purely on the measurement of weight, measured in kilograms, divided by the square of the individual’s height in meters. This measurement works as a rough estimate of fitness for the majority of people, but is not accurate or appropriate for some circumstances.

Having a large amount of lean muscle is healthier than having a large amount of body fat.
Having a large amount of lean muscle is healthier than having a large amount of body fat.

The problem with this measurement is that it leaves no room for very athletic or very sedentary people to have differing body compositions, and therefore differing levels of health. For instance, an extremely sedentary person may be composed of 35 percent body fat with very little lean muscle, and yet weigh the same as a bodybuilder with 6 percent body fat and a huge amount of lean muscle. If these two individuals are the same height, they will also have the same BMI, and will be judged to be at an equal fitness level.

The human muscular system.
The human muscular system.

Currently, the fitness industry is heavily populated with products claiming to allow the user to rid his or her body of fat while preserving the lean muscle, resulting in a sculpted, toned physique. This goal is what most fitness trainers and athletes recommend working toward. It is considered to be medically sound advice, because it is much healthier for a person to have a large amount of lean muscle than it is for someone to have a large amount of body fat. Many fitness professionals, doctors, and health institutions readily provide information on what body fat percentage or ratio of fat mass to lean muscle and other lean body mass is healthy for each gender at varying age groups and fitness levels.

Discussion Comments

anon359227

There is so much information available on muscle building and diet nutrition it is becoming confusing. The fact is that most everyone is making things up or talking about what has or is working for them at the moment. The majority of individuals have a hard time relating to or implementing what they learn.

The truth is that many of the supplements available do not work and many so-called experts, including doctors, are lying to us just to keep us paying them. The ultimate fact is that unless you have the same genetic make up as that "hunk" or "brick house" you will never see the same results.

kferguson

@geronimo 8: There are plenty of techniques he could try, for instance, a weightlifting and cardio program supplemented by some diet changes.

A fitness coach or nutritionist will be able to assess your husband's needs and tailor a plan specifically for him.

kferguson

@claire 24: I believe BMI is still used as a rough estimate of a person's physical fitness level because it is "close enough" for most average people. The ones who are dramatically incorrect are generally pretty obvious just by looking at them (e.g., take the heavily muscled person with an obese BMI - it will be a noticeable error).

For a more accurate estimate of your lean mass and fat mass proportions, try getting a body fat percentage measurement done.

kferguson

Yes, exactly, upnorth31. A person weighing 250 pounds might be considered obese because of his high body weight, but in reality he might just have a large amount of lean muscle and very little fat mass.

geronimo8

My husband is in the process of trying to lose weight while building lean muscle.

Are there foods he could be eating or exercises he could be doing that will help him to do this more efficiently?

claire24

I never realized how flawed the use of the body mass index could be. If it could show that an active, very athletic person is at the same fitness level as a couch potato, I wonder why the BMI is used at all anymore.

I think it's very important to take into account a person's amount of body fat and lean muscle.

upnorth31

I've always thought that a person having a lot of lean muscle could have a very deceiving body weight. I've always heard that muscle weighs more than fat, so a person who looks lean and in shape may weigh more than what you would normally consider to be a healthy weight.

It is healthy though to have a higher weight, if it's a result of lean muscle instead of fat.

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    • Having a large amount of lean muscle is healthier than having a large amount of body fat.
      By: ruigsantos
      Having a large amount of lean muscle is healthier than having a large amount of body fat.
    • The human muscular system.
      By: adimas
      The human muscular system.
    • BMI is not always the best measure of physical fitness, since muscle weighs more than fat.
      By: papa
      BMI is not always the best measure of physical fitness, since muscle weighs more than fat.
    • Muscle mass is denser than fat tissue, thus it weighs more.
      By: Christopher Howey
      Muscle mass is denser than fat tissue, thus it weighs more.
    • The percentage of lean muscle a person carries can impact their weight.
      By: jedi-master
      The percentage of lean muscle a person carries can impact their weight.
    • Lean muscle is what most fitness trainers and athletes recommend working toward.
      By: berc
      Lean muscle is what most fitness trainers and athletes recommend working toward.