Lean body mass

Lean Body Mass (LBM) refers to the total weight of a person's body minus all the weight due to their fat mass. It includes the weight of all the organs, skin, bones, body water, and muscles.

Definition

Lean body mass is a component of body composition, measured by subtracting body fat weight from total body weight: total body weight is lean plus fat. In physical fitness, body composition is used to describe the percentages of fat, bone, water, and muscle in human bodies.

Importance of Lean Body Mass

Lean body mass is important because it is predominantly composed of muscle mass. Muscle mass is a major contributor to total energy expenditure. Lean body mass has been shown to be a major determinant of the rate of metabolism in the body.

Measurement

There are several methods to measure lean body mass, including Dual-energy X-ray absorptiometry (DXA), Bioelectrical impedance analysis (BIA), and skinfold methods. DXA is considered the most accurate method, but it requires specialized equipment and trained professionals. BIA is less accurate but is a common method due to its simplicity and speed.

Factors Affecting Lean Body Mass

Several factors can affect lean body mass, including age, gender, and level of physical activity. Age is associated with a decrease in lean body mass, in part due to decreased muscle mass. Men generally have a higher lean body mass than women due to higher muscle mass. Physical activity can increase lean body mass by stimulating muscle growth.

See Also

• Body composition
• Muscle mass
• Metabolism
• Dual-energy X-ray absorptiometry
• Bioelectrical impedance analysis