Protein timing: does the hour after training matter?

For about twenty years the rule in every gym was the same: finish your last set, and you have thirty minutes to get protein in before the workout is wasted. People jogged to the changing room with a shaker bottle. Some still do. The idea even had a name, the anabolic window. When researchers finally tested it over months in the gym instead of hours in a lab, there was very little of it left.

The short version: the window exists, but it is closer to a barn door. Here is what the research found when it went looking, and the few situations where the clock is still worth a glance.

Where the thirty minutes came from

The idea was not invented by a supplement company, although supplement companies were delighted to adopt it. It came from real lab work. Muscle is more responsive to protein after it has been trained, and early studies that fed people straight after a session, often after an overnight fast, saw a bigger response than studies that made them wait. From there it was a short step to "sooner is better" and an even shorter one to "later is useless".

The trouble is that those were studies of a few hours in a lab, not of months in a gym. Whether any of it shows up as more muscle at the end of a training block is a different question, and it needed different studies.

What happened when it was tested properly

In 2013 three researchers pooled every controlled trial they could find in which one group took protein close to training and another did not: twenty-odd studies, several hundred lifters. On a first pass, timing looked like it helped muscle growth a little. Then they accounted for one thing, and the effect disappeared. In most of the trials the timed group was simply getting more protein in total. Once the day's intake was matched, when it arrived made no measurable difference to strength or to size. Total protein was the strongest predictor of who grew.

A later trial tested the window head on. Trained men took the same twenty-five grams of protein either immediately before or immediately after each session for ten weeks. The two groups ended up in the same place on every measure. Its authors drew the obvious conclusion: if there is a window, it is several hours wide, and where it sits depends on when you last ate.

Why the clock matters so little

Two reasons. The first is that a meal is not an instant. Protein from a normal lunch is still being digested and delivered to your blood three or four hours later. If you had a proper meal a couple of hours before training, you are, in every way your muscles care about, still eating it when you rack the last bar.

The second is that trained muscle stays receptive for a long time. One well-known study found the heightened response to protein still there a full day after a hard session. The opportunity is not thirty minutes long. It is most of tomorrow.

Put together, the practical guidance from the people who did the pooling is almost boring: have a meal with a proper serving of protein, roughly 20 to 40 grams, somewhere before training and another somewhere after, and try not to leave much more than three or four hours between the two, session included. If both are big, mixed meals, they stretch that to five or six.

Put a clock on it. A snack at five, a session from six to seven and dinner at eight is three hours from one to the other, comfortably inside. Breakfast at seven, a session at nine and lunch at half past twelve is five and a half, which is fine if breakfast was a real meal. Lunch at one, a session at six and dinner at eight is seven hours with nothing in them, and that is the case the guidance is about. A yoghurt, a sandwich or a shake at four or five closes it, and that is all the timing most people will ever need to do.

When timing is worth a thought

• You train fasted, first thing. If the last protein you had was dinner, there is no earlier meal still doing its work. Eating soon after makes sense. It still does not need to be a sprint.
• Your meals are far apart. A lunch at noon and a session at seven with nothing between is the gap the guidance warns about. A snack with some protein in the afternoon closes it.
• You are short on the day. A serving before bed is digested and used overnight, as one study of young men showed. That is not a magic hour. It is one more chance to reach a total you were going to miss.

What deserves the attention instead

The day's total. We went through how much protein lifters actually need in an earlier post, and the uncomfortable finding there applies here too: most people who worry about the window are not reaching the amount the window is supposed to protect. Fretting over minutes while a third of the day's protein is missing is fixing the small problem and leaving the big one.

So eat before, eat after, spread it over the day's meals, and stop running to the changing room. If your Tuesday added up, the hour it happened in was fine.

Sources

• Schoenfeld BJ, Aragon AA and Krieger JW, "The effect of protein timing on muscle strength and hypertrophy: a meta-analysis", Journal of the International Society of Sports Nutrition, 2013. pubmed.ncbi.nlm.nih.gov/24299050
• Schoenfeld BJ et al., "Pre- versus post-exercise protein intake has similar effects on muscular adaptations", PeerJ, 2017. pubmed.ncbi.nlm.nih.gov/28070459
• Aragon AA and Schoenfeld BJ, "Nutrient timing revisited: is there a post-exercise anabolic window?", Journal of the International Society of Sports Nutrition, 2013 - the three-to-four-hour guidance. pubmed.ncbi.nlm.nih.gov/23360586
• Burd NA et al., "Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men", The Journal of Nutrition, 2011. pubmed.ncbi.nlm.nih.gov/21289204
• Res PT et al., "Protein ingestion before sleep improves postexercise overnight recovery", Medicine and Science in Sports and Exercise, 2012. pubmed.ncbi.nlm.nih.gov/22330017