Lean Body Mass (LBM)
Definition
The total weight of your body minus all fat weight, including muscles, bones, organs, water, and other non-fat tissues.
Formula
LBM = Total Body Weight - (Total Body Weight × Body Fat %)Lean body mass represents everything in your body that is not fat: muscles, bones, organs, blood, water, and connective tissue. It is calculated by subtracting fat mass from total body weight. LBM is a more useful metric than total weight for assessing fitness and health.
LBM determines your basal metabolic rate more accurately than total body weight because muscle tissue is metabolically active, burning calories even at rest. More lean mass means a higher metabolism, which is why strength training is emphasized for long-term weight management.
Tracking LBM over time helps assess whether weight changes are coming from fat loss or muscle loss. During dieting, losing LBM is undesirable as it reduces metabolism and functional strength. Adequate protein intake and resistance training help preserve LBM during a calorie deficit.
Related Calculators
Related Terms
Body Fat Percentage
healthThe proportion of your total body weight that is composed of fat tissue, a more accurate indicator of fitness than weight alone.
BMR (Basal Metabolic Rate)
healthThe number of calories your body needs to perform basic life-sustaining functions at complete rest, such as breathing, circulation, and cell production.
Metabolic Rate
healthThe speed at which your body burns calories for energy, encompassing basal metabolic rate plus the energy used for activity and digestion.
Protein
healthOne of the three macronutrients providing 4 calories per gram, essential for building and repairing muscles, tissues, enzymes, and hormones.
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