Protein Metabolism

Dietary protein is broken down to amino acids and either used for tissue synthesis or oxidised for energy. Net balance depends on total intake, distribution across meals, leucine content per meal and — critically — energy availability, since insufficient calories divert amino acids to fuel. Older adults develop anabolic resistance and need more protein per meal (roughly 0.4 g/kg) to trigger the same synthetic response. Very high intakes are safe in healthy kidneys but must be reduced in chronic kidney disease.

1) Set total intake: 1.2-1.6 g/kg for general health, 1.6-2.2 g/kg when training or dieting, and toward the top for older adults. 2) Distribute across 3-4 meals of 25-40g rather than one large serving; per-meal leucine threshold governs the synthesis response. 3) Eat enough total energy — protein is spared for building only when calories are adequate. 4) Combine with resistance training; protein without a mechanical stimulus mostly gets oxidised. 5) Prioritise complete protein sources or combine plant sources to cover leucine and lysine. 6) Skip amino acid blends and BCAAs if whole protein intake is sufficient — they add nothing. 7) Reduce intake only if you have kidney disease, on medical advice.

• •Total daily protein intake
• •Even distribution across meals
• •Resistance training
• •Adequate total energy
• •Prioritising complete protein sources
• •Adequate hydration