Lean body mass (LBM) includes all body tissue except fat and accounts for 75% of normal body weight. Skeletal muscle comprises 50% to 60% of LBM by weight. In the absence of nutrient intake, muscle is the principal repository of protein and amino acids used in protein synthesis. As such, muscle plays a central role in protein metabolism.

Management of Muscle Mass Health

Muscle mass is maintained by a balance between muscle protein synthesis and muscle protein catabolism. Both resistance exercise and amino acid loading can enhance protein balance, however, resistance exercise is challenging, specially during acute illness. 

Skeletal muscle wasting and weakness commonly occur due to:

1.Immobilization and disuse
2.Malnutrition
3.Age-related sarcopenia
4.Cancer cachexia
5.Early critical illness

Experimental research suggests that HMB supplementation helps avoid muscle mass loss or increase muscle mass and enhances muscle strength, physical function, and performance. 

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