You may be thinking that your lean body mass is your ideal weight or your weight if you were a true "lean machine." Well, it’s not. Your lean body mass is sum of the nonfat parts of your body like muscle, organs, blood and water.

Since it’s not possible to weigh these parts separately, researchers have developed formulas for calculating lean body mass based on highly scientific measurements of human body composition. But it is important to note that they are based on "averages.” These formulas predict the lean body weight "average" based on data collected from a group of people with similar height and weight.

You, on the other hand, might have denser bones, more muscle, bigger internal organs, or any number of differences that will make you above or below this average. So keep in mind that these are just estimates.

Knowing what your lean body mass and your body fat percentage are can help you and your doctor design realistic weight management goals.

WHAT IS LEAN BODY MASS?

Lean body mass is commonly used to describe the muscles in your arms, legs, back, neck and abdomen. But actually it also includes your heart muscle, and the tissues of your other internal organs as well as water, and bone. This is the part of your body you want to preserve or expand.

How much lean body mass you have is the most important factor in determining your metabolism (the rate at which you burn the calories). The higher the amount of your lean body mass, the higher your metabolic rate and the more calories you will burn when you are sitting or lying down. This higher metabolic rate makes it easier to maintain your weight.

Want to build up your lean body mass? The good news is that you can increase the amount and the strength of your muscles through a regular program of strength training - also known as "resistance" training.