Nutrient timing is a popular nutritional strategy that leads to the debate about the correct time to consume dietary protein around an exercise session for the best results.
This is an important topic as it has great influence upon how well damaged muscle tissue is repaired and rebuilt. Ideal protein timing should, in theory, significantly enhance body composition and training adaptations.
Specifically in regard to protein, several researchers have even made reference to an “anabolic window of opportunity” in the immediate post-exercise period whereby a limited time exists consume protein and optimize recovery and training adaptations.
However, does it really matter if you consume protein immediately after a workout? Can you get the same effect by consuming protein before the workout? Let’s find out:
The Case For Post-Workout Protein Ingestion
The post-exercise period is often considered the most critical part of nutrient timing as the muscles are in their most desperate state for repair.
This led to the theory of the “anabolic window of opportunity”, which states nutrients must be consumed immediately post-exercise to take advantage of the super-compensated effects the nutrients will have on recovery [1] [2].
To an extent, this is true, as after a workout the muscle is in a net state of protein breakdown, however the potential for muscle protein synthesis is significantly elevated [3].
Resistance training alone has been shown to promote a twofold increase in protein synthesis following exercise [4].
This is because training appears to have stimulatory effects and increases the sensitivity of muscle tissue to the presence of amino acids from dietary protein [5].
Therefore, it seems logical to immediately consume protein post-exercise to inhibit muscle breakdown and make use of the increase in muscle protein synthesis.
However, it is key to note that increases in muscle protein synthesis from protein intake are seen for at least 24 hours post-exercise – not just in the immediate post-training period [6].
But this does not oppose the fact that in most situations consuming dietary protein immediately after training can quickly initiate the recovery process and enhance muscular growth compared to delaying protein intake [7].
The studies which analyze the extent of this benefit are somewhat contradicting, and many studies will fail to detect any increases in skeletal muscle mass from immediate consumption versus a delay, which suggests that the importance of post-workout protein is dependent on other variables [8] [9].
This leads on to the conversation of pre-exercise protein intake and how it may augment the nutritional requirements post-exercise.
The Case For Pre-Workout Protein Ingestion
Depending on its size and composition, there is reason to believe that the pre-exercise meal can conceivably function as both a pre- and an immediate post-exercise meal.
The reason for this is because of the time course of the foods digestion and absorption, which can easily persist well into the recovery period.
The first evidence for this was the observation that a relatively small dose of essential amino acids (6 grams) taken immediately pre-exercise could effectively elevate amino acid levels in the blood by around 2 hours after exercise finished [10].
These same findings have since been repeated with whey protein, as opposed to only essential amino acids, and in this case even managed to extend amino acid uptake into muscle tissue until 3 hours post-exercise [11].
This research adds an additional variable and context to the conversation of the post-workout “anabolic window” that was first proposed.
Therefore the immediate importance of dietary protein in the post-exercise period is partly dependent on the timing and composition of the pre-workout meal [12].
Other factors such as the duration of exercise, and the recovery times before upcoming exercise sessions, may also influence the need for protein around training.
Collectively, the available data lack any consistent indication of an ideal post-exercise timing scheme for maximizing muscle protein synthesis [13].
The Main Takeaway
While there is an abundance of short-term studies on this topic, there is a lack of long-term trials that compare the biological effects and practical implications of various pre- and post-exercise timing schemes.
The results from the research so far show that pre- and post-exercise protein ingestion are extremely important in various contexts, and the use of one can impact the importance of the other.
If exercise is taking place fasted (no prior food) or after a long period without protein, consuming post-exercise protein is essential to stop muscle protein breakdown and increase muscle protein synthesis.
However, consuming protein before exercise can reduce the importance of immediate protein consumption post-exercise.
To ensure people are getting the best adaptations and recovery from training, it is advised to consume protein in the pre-training and post-training period. This will guarantee that people do not miss out on potential spikes in muscle protein balance by unnecessarily missing 1 of these 2 meals.
A “better safe than sorry” approach is best until more research on this topic gives a clearer indication of the exact practical steps that need to be taken.
Conclusion
For many years it was always thought that immediate protein intake after a workout was necessary to recover properly.
However, newer research shows that if protein is consumed prior to exercise, the immediate need for protein after a session is reduced.
The problem is that the practical implications of such knowledge is not well established and leaves a large grey area that can easily cause confusion.
At this point it is recommended to consume a protein-containing pre-exercise meal ~2 hours before training, followed by an immediate post-exercise protein meal or shake, to get the best of both worlds.