Research from Maastricht University Medical Centre has shown that the pattern of protein intake across the day, not just the total daily amount, significantly affects muscle protein synthesis rates in older adults. Older muscle is less sensitive to dietary amino acids, requiring a higher per-meal dose of protein to maximally stimulate muscle protein synthesis. This anabolic resistance means that spreading protein evenly across three larger meals produces better outcomes than concentrating it in one or two meals.
The Per-Meal Leucine Threshold
Leucine, the branched-chain amino acid most responsible for triggering mTOR, the primary regulator of muscle protein synthesis, has a threshold effect. Below approximately 2.5 to 3 grams of leucine per meal, the muscle-building signal is not maximally activated. Above this threshold, no additional signal is produced. A meal providing 30 to 40 grams of high-quality protein from animal sources or soy will typically deliver this leucine threshold. A meal providing 15 to 20 grams will often not.
The Pre-Sleep Protein Finding
A series of studies from Maastricht University found that consuming 40 grams of casein protein immediately before sleep significantly increased muscle protein synthesis rates during overnight sleep compared to a protein-free control. Casein is a slowly digested protein found in milk, Greek yoghurt, and cottage cheese that provides a sustained aminoacidaemia through the night. This finding is particularly relevant for adults over 35 who are trying to counteract age-related muscle loss.
- Aim for 30 to 40 grams of protein at each of three daily meals
- Include a protein-rich food at breakfast rather than a carbohydrate-dominant meal
- Consider Greek yoghurt, cottage cheese, or casein protein before sleep if muscle preservation is a priority
- Space meals approximately 4 to 5 hours apart to allow complete aminoacidaemia clearance and re-stimulation at the next meal