Protein Timing

Muscle protein synthesis (MPS) is elevated for 24 to 48 hours following resistance training, not just in the hour immediately after a session. Each protein-containing meal drives a burst of MPS that lasts roughly 3 to 5 hours before returning to baseline. Providing the leucine threshold, approximately 2.5 to 3g of leucine, which corresponds to roughly 30 to 40g of protein from a complete source, at each meal triggers a near-maximal MPS response. Smaller doses produce a smaller spike; doses beyond 40g do not further elevate synthesis rates within a single meal, though additional protein may contribute to whole-body nitrogen retention.

The "anabolic window" concept, the idea that consuming protein within 30 minutes of training is dramatically superior to any other time, originated from studies comparing post-workout protein to no post-workout protein at all. When pre-workout protein is consumed, as in most real-world training scenarios, the anabolic window extends substantially. A 2013 meta-analysis by Aragon and Schoenfeld found that total daily protein intake was a far stronger predictor of muscle gain than timing around workouts, though proximity to training still showed a small but consistent advantage when all other factors were equal.

Distribution across the day is the most robustly supported timing principle. Consuming 160g of protein in two large meals produces meaningfully less total MPS stimulation than the same 160g spread across 4 to 5 meals, because the MPS burst per meal is capped and multiple peaks across the day drive more total synthesis. Pre-sleep protein is an area of strong emerging evidence: 40g of casein protein before bed has been shown in several studies by Res, Snijders, and van Loon to increase overnight MPS and improve next-morning strength in resistance-trained individuals, capturing an otherwise unused synthesis window.