Protein Timing & Metabolic Rate in Aging Women

Protein distribution across meals — not just total daily intake — appears to be a significant determinant of muscle protein synthesis efficiency. A 2023 study in the Journal of Nutrition found that evenly distributing protein across three meals (30–40 g per meal) stimulated greater 24-hour muscle protein synthesis than an equivalent protein dose front-loaded into one or two meals — even when total intake was identical.

The theoretical maximum for muscle protein synthesis from a single dose of protein is approximately 20–40 g in younger adults, but appears to be higher in older adults — a phenomenon called 'anabolic resistance,' where aging muscle requires more protein per dose to achieve the same synthetic response. This means older women need not only more protein overall but also more protein per meal to reliably trigger MPS.

“Evenly distributing protein across three meals stimulated greater muscle protein synthesis than loading the same dose into one or two — even with identical total intake.”

The thermic effect of food (TEF) — the metabolic energy cost of digesting, absorbing, and processing nutrients — is highest for protein (20–30% of calories consumed), compared to carbohydrates (5–10%) and fat (0–3%). A high-protein diet therefore provides a meaningful increase in resting metabolic rate — estimated at 80–100 kcal/day extra in studies of isocaloric high vs. low-protein diets.

Metabolic rate declines with age — approximately 2–3% per decade after 20 — primarily due to the loss of metabolically active lean mass. Preserving or increasing muscle mass through protein and resistance training is the most evidence-based strategy to counteract this decline. VITA's approach — high protein at every meal, every day — directly addresses this mechanistic target.