Protein Part III- How much does acute intake matter post-run?

The days of my protein rambling have almost come to an end! In my last post, I discussed how much protein should be ingested/day and how that protein should be distributed. The article before that discussed whether acute protein consumption before and activity enhances performance.

In my final article in the protein series, I want to discuss acute protein ingestion related to an acute bout of exercise. This is something that I get asked about all the time at the club: is it important to quickly ingest protein directly after a given activity to enhance recovery from that bout of training?

What the research shows:

We know that there are two major triggers for muscle protein synthesis:

  • As I wrote about in my last article, we know for a fact that protein ingestion stimulates muscle protein synthesis.
  • There are plenty of studies which show that resistance training on it’s own also induces muscle protein synthesis.

However, when you combine the two stimuli in close proximity, is there merely a summative effect of the two separate muscle-building signals OR is there an additional benefit to combining the two?

As studies like this 2011 one show, it does make sense in theory that if you increase the concentration of amino acids (building blocks for proteins) in the blood while the anabolic signals triggered by exercise are high, then the body will further be able to take advantage of BOTH signals.

Study #1: Acute Protein vs. Sugar Water

Take for instance this study published in 2007 in the American Journal of Clinical Nutrition. In the study, 56 healthy males were followed for 12 weeks as they trained 5 days/week. They were then given something to drink directly after and 1 hour post-workout, which was either:

  • Milk
  • Soy protein (same caloric and protein composition to the milk)
  • A sugary drink that had the same caloric content as the other 2 drinks

The researchers found that the Type 2 muscle fibre area improved in all 3 trials, but with the milk subjects showing the most improvement. Not only that, Type 1 fibre area (slow twitch- important for us runners!) increased only in the soy and milk groups with milk once again coming out on top.

So, what this study shows is that it’s not just a matter of getting anything in, but that ingesting protein (and the optimal form of protein) in close proximity to the activity will enhance muscle protein synthesis.

Based on this, sure; try to ingest protein within the anabolic window post-training. However, just how wide is this window, and how important is it focus on just that one feeding post-exercise?

Study #2: How wide is the protein ingestion window?

If you are training multiple times in one day, acute carbohydrate and fluid ingestion is important down to 15-minute intervals (or less). However, with protein, it seems we have significantly more wiggle room from an acute ingestion standpoint, and less wiggle room in terms of our overall consistent protein load and the associated long term adaptation.

Take for instance this 2011 study published in the Journal of Nutrition. The researchers made the subjects work out at a few different intensities, and then measured the elevation in muscle protein synthesis over the course of the next 24 hours.

I stole this graph from their article:

In this graph, MPS= muscle protein synthesis.

Without getting into the nitty gritty, as you can see, the elevated state of protein synthesis IS the highest within close proximity to the training stimulus (but not directly after).

However, what this and many other studies like it also show is that the elevated period of muscle protein synthesis after a bout of training stays quite elevated for 24 hours and beyond. Not only that, the rate of decline of the muscle building state is actually not very steep at all, and neither is the rate of decline of the boost provided by protein feedings.  Your window to exploiting the exercise-induced anabolic signal is wide open!

Practical Applications:

So, is it a mistake to focus on ingesting protein directly after training? Definitely not. However, I think it’s important to note the key, basic physiological re-fueling difference between protein consumption and carbs/fluid intake.

Carb and fluid replenishment are imperative for acute recovery from a bought of exercise. If you are pulling a double day, or have a busy day at work after a hard morning workout, hydrating and replenishing your glycogen stores and fluid loss should be priority #1 to allow for performance in that next bout of activity. Special carb and fluid intake (beyond what is required to sustain your normal daily life) should be viewed as an acute reaction to an acute bout of exercise.

Muscle protein synthesis is a long term, more continuous process than simply toping up glycogen or rehydrating. Muscle protein synthesis and breakdown is continuously happening.

So yes, try to exploit the acute additive effects you get from ingesting protein after an activity. But also keep in mind that the window for the addictive impact of ingesting protein is quite broad. Waiting 60 minutes rather than 30 minutes to ingest your 1st protein load post-training isn’t a major mistake. On the other hand, making sure you ingest protein within 30 minutes, but then failing to consume any additional protein for another 8 hours would be much more significant mistake.

The one-and-done protein load in close proximity to training should not be the priority. Rather, because of the constant protein turnover that our muscles go through, and the repeated bouts of damage run training induces, the focus should be on consistently getting protein rich meals at the appropriate volume 4-6x/day (check out more details here).