Executive summary

Skeletal muscle represents about 40% of the human body weight and is responsible for movement and postprandial glucose processing.^{1, 2} It is the principal protein reservoir to replace blood amino acids,³ the precursors for hepatic gluconeogenesis.⁴ Adequate muscle mass is paramount to maintain plasma glucose concentration, conversely, depletion is incompatible with life. Warsaw ghetto studies suggest that death from starvation occurs when muscle protein breakdown becomes inadequate to maintain supply of gluconeogenic precursors.⁵ Losing muscle occurs naturally with age and can lead to decreased strength and functionality. After 30 years of age, there is a shift towards degeneration, leading to a net loss of muscle mass and strength.⁶ This muscle wasting in ageing, but otherwise healthy individuals, is referred to as sarcopenia.