Pre-workout vs. post workout proteins

The benefits of protein and/or amino-acid drinks have been proven by so many scientific studies that we can safely say protein supplements have their place in bodybuilding nutrition.

What has been studied to much lesser extent is the ideal timing of protein ingestion. In this article we will try to summarize our current knowledge and draw some conclusions.

Basics: fasted or fed state?

Not long ago the prevalent opinion among the coaches in many sports has been that fasted state is preferable if not inevitable during physical training. The rationale was something like this: digestion is energetically demanding process; body needs to rest to digest properly and the digestive tract needs to be congested (full of blood) in order to work correctly. Physical activity will draw the blood and energy to other parts of the body (muscles) and it must be therefore conducted in fasted state.

On the other hand, energy-replenishing supplements have been on the market for many decades and even before the onset of supplement market athletes have been using sugar to quickly replenish their energy reserves.

Most of us know the typical tiredness which comes after eating a heavy meal. It is no wonder that the most industrious nations (like Dutch and Germans) only eat salads or sandwiches for the lunch on working days. Heavy meals are only served in the evening or during weekends. In countries like France, where rich lunches are part of national identity, enough time has traditionally been spent on the meal (so that a person doesn’t return to work immediately after eating).

This is something we have to take seriously. Pre-workout meal may not be a bad idea but it should never be a large and heavy meal which will impair the training and will not be digested properly. Otherwise all you get is peptic ulcer and little muscle growth.

Why post-workout drink?

The theory behind post-workout drinks is based on two well established facts: first, the ingestion of protein will lead to protein synthesis in the muscle (anabolic effect) – even in absence of resistance training (although to much smaller extent) and second, resistance training increases the muscle protein synthesis rate.

The first trials with resistance exercise measured the protein synthesis rate immediately after the exercise, which makes sense if you wish to avoid possible mistakes and various influences (diet, lifestyle of subjects etc). And since they concluded that the muscle protein synthesis is significantly increased after the workout, athletic community adopted the rule to ingest proteins as soon post-training as possible.

There is probably nothing wrong with this approach especially as protein drinks often contain also other ingredients for immediate replenishment of depleted energy sources.

However, it is important to mention that newer trials studied muscle protein synthesis 24 hours after the workout and it turned out that the protein synthesis rate is still significantly increased (e.g. Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men, N.A. Burd and colleagues, 2011).

The fact that protein synthesis is elevated (of course, only if enough protein is present) 24 hours after the workout shouldn’t be mistaken for statement that “protein synthesis is elevated only for 24 hours after workout”. No. We simply know that after 1 day, the body is still in anabolic state. This state can last 3 days post-workout – we don’t really know yet.

What is sure, the window for protein supplementation is relatively wide.

Protein/amino acid availability during the workout

Now, it seems quite reasonable to expect that some protein supplementation during the workout might be beneficial to muscle growth.

If we want to supply the body with protein building blocks and timing is of importance, we have to consider the process of protein breakdown. So we would expect that free amino acids will be available almost immediately, whey protein hydrolyzate very soon after ingestion and whey protein isolate within 30 to 60 minutes. Casein would not be digested so fast and it’s not suitable for this form of supplementation.

K.D. Tipton & colleagues from University of Texas experimented with amino acids given immediately before exercise and immediately after the exercise. The trial showed that protein synthesis was greater in the pre-workout group. The difference in phenylalanine uptake by the muscle was significant: 209 comparing to 81.

When the same trial was repeated several years later by the same team with proteins instead of free amino acids, the differences between pre-workout group and post-workout group were negligible.

The most likely explanation is that the protein simply didn’t break down soon enough to be available during the workout.

Our verdict

Based on current knowledge bodybuilders should train in fed state but not very soon after a large meal. Dose of free amino acids (BCAA or full-spectrum AA) should be ingested immediately before the workout. Protein supplementation and high-protein food should be ingested in several doses during the following 24 hours (including on non-training days).