MECHANISM ENGINE

What Is Sarcopenia?

Nobody warns you about this one properly. Weight loss gets all the attention. Muscle, quietly draining away in the background if you’re not doing anything to keep it, gets almost none, until it’s already a problem.

Evolutionary Waste Disposal

The body treats muscle as expensive to maintain, and expensive things that aren’t being used get marked for removal. Unused muscle, to your body, looks like evolutionary waste, tissue that costs energy to keep around but isn’t earning its keep. From your late thirties onward, without a reason to hang on to it, that muscle starts getting quietly stripped back, a slow decommissioning rather than a dramatic loss. The only argument that actually works against this is regular, ongoing demand. Give the body a reason to keep the asset, and it generally does.

Sarcopenia is the progressive loss of muscle mass and strength associated with ageing, typically beginning around the mid-thirties and accelerating from the fifties onward without intervention. It’s driven by reduced physical activity, inadequate protein intake, and hormonal changes. Muscle is also metabolically active tissue, so its loss is linked with reduced insulin sensitivity and a lower resting metabolic rate, not just reduced strength.

NHS and NICE materials on healthy ageing identify resistance-based activity and adequate protein intake as the primary evidence-based levers for preserving muscle mass, with benefits demonstrated even when started later in life.

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Related mechanisms

Educational only, not medical advice. Speak to your GP before changing your fasting pattern, diet, or medication.

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What this is based on

NHS and NICE guidance, cross-referenced against Neil’s own NHS blood test record going back to April 2012. See the full timeline and current numbers.