Post-Workout Protein Timing Calculator

Muscle protein synthesis, MPS, is the process of building new muscle tissue. Two things drive it: a resistance training stimulus and dietary protein. Getting both of those roughly right matters far more than getting the timing exactly right.

How much protein per meal

Work by Stokes, Phillips and others puts the per-meal dose that maximally stimulates MPS at 0.25 to 0.40 g of protein per kg of body weight. This calculator uses 0.4 g/kg, the top of that band, and the reason is worth explaining because most calculators quietly use the bottom of it.

Leucine is the actual trigger, and the arithmetic has to work

MPS is switched on by leucine crossing a threshold, not by protein in the abstract. That threshold is roughly 2.5 g of leucine for a young adult and closer to 3 to 4 g for someone over about 60, whose muscle is less responsive to the same signal.

Now the arithmetic. Leucine content varies by source:

At 0.25 g/kg, a 75 kg person eating chicken gets 19 g of protein and about 1.5 g of leucine, which does not reach the threshold. At 0.4 g/kg they get 30 g and 2.4 g, which just about does. That gap is why this calculator uses the higher figure and then checks the leucine result against the threshold instead of assuming it clears.

You still do not need the mythical 60 g servings that supplement marketing promotes. Above roughly 0.4 g/kg the extra amino acids are oxidized rather than built into muscle.

The 0.4 figure is used here to decide how many meals your daily total needs splitting into. The actual per-meal dose then comes from dividing the total by that count, which lands close to 0.4 g/kg and, more importantly, means the meal plan and the daily target are the same number rather than two numbers that disagree by 10%.

The anabolic window is wider than you were told

The old 30-minute window was overstated to the point of being wrong. Current evidence puts the period of elevated protein sensitivity at 4 to 6 hours after training, and possibly up to 24. If you ate a protein-containing meal 1 to 2 hours before training, that meal is still being digested and you have plenty of time. Train genuinely fasted and the picture changes: getting protein in within 30 to 60 minutes does matter, because there is nothing circulating.

Daily total

The cut figure being the highest surprises people. In a calorie deficit the body is more willing to break down muscle for fuel, so protein needs go up rather than down. This is the single most common mistake in a diet phase.

Spreading the daily total across 4 to 5 meals produces more total daily MPS than the same amount in 2 large meals, because each meal has to clear the leucine threshold separately to count.