Sarcopenia — age-related muscle loss — begins in your 30s and accelerates after 50. By 80, most people have lost 30-50% of their muscle mass. This isn't just a cosmetic issue: muscle loss increases fall risk, reduces metabolic rate, worsens insulin sensitivity, and is strongly associated with earlier death.
Muscle is your metabolic armour. It's your largest glucose sink, your primary calorie-burning tissue, and your physical reserve for illness and injury. Losing it makes every aspect of ageing harder. Research from the Journal of the American Medical Directors Association identifies low muscle mass as one of the strongest predictors of mortality in older adults.
The Recommended Dietary Allowance of 0.8g per kg bodyweight was established to prevent deficiency in sedentary young adults. For active people over 40, it's woefully inadequate. Research consistently shows that 1.2-1.6g per kg bodyweight is needed to maintain muscle mass, and even higher amounts (up to 2.2g/kg) are optimal during weight loss to preserve lean tissue.
The issue is anabolic resistance: as you age, your muscles require a stronger protein signal to trigger muscle protein synthesis. Young adults can build muscle from 20g of protein per meal. Older adults need 35-40g — and the protein must contain at least 2.5g of leucine (the amino acid that triggers the mTOR growth pathway).
Spread protein evenly across 3-4 meals rather than loading it at dinner. Each meal should contain 30-40g of high-quality protein with adequate leucine. Best sources: eggs, chicken, fish, Greek yoghurt, whey protein, and lean beef. Plant proteins work but require larger portions to hit leucine thresholds.
A practical daily target for a 75kg person over 40: 90-120g of protein per day. Start breakfast with protein (eggs, Greek yoghurt, protein shake) instead of toast and cereal. Add a protein source to every meal and snack. Resistance training 2-3 times per week is the essential partner — protein without the training stimulus is far less effective at maintaining muscle.
Anyone interested in evidence-based longevity strategies, health optimisation, and understanding the latest research on ageing and healthspan.
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