Post- exercise anabolic window?

Meyken Houppermans, PhD. CrossFit Level 3 Trainer.
Founder and Head Coach
Do you need protein immediately after a workout to build muscle mass? It depends.

Eat breakfast

To build muscle mass and optimize recovery after a training session, the body needs protein in combination with carbohydrates immediately following the training session. At least, according the theory of Post-exercise anabolic window that states the body will absorp all nutrients to build muscle mass.

This is not quite correct.

Research shows little is known about the post-exercise anabolic window. Research results are ambiguous and individual factors play an important role. What is known is, training after a period of fasting with a completely empty stomach and empty glycogen stores in the muscles, taking protein and carbs directly after a training session does actually have some effect. It reduces the risk of the body staying in a catabolic mode (muscle breakdown). [1]

In people who have a late dinner and workout the morning after, there is no post anabolic window where everything eaten is absorped 100%. And certainly not if the athlete has breakfast before the training session. In some cases, breakfast can be considered a post-exercise meal, because the processing of it also takes place after the training session. Therefore it’s important to have a proper breakfast that consists of carbohydrates, proteins and fats. The additional benefit is more energy for the training session. (Timing is everything)

The best results

The best effects on building muscle mass and strength is the combination of consistently doing (strength) training and having a well balanced diet with a sufficient amounts of protein. (Animal or plant protein: which is better for athletes?) It is not just a matter of what the athlete eats directly after the training session. A lousy diet throughout the day can have a significanT negative impact on training results.

Create your own health!©


Aragon AA, Schoenfeld BJ. Nutrient timing revisited: is there a post-exercise anabolic window? J Int Soc Sports Nutr. 2013 Jan 29;10(1):5. doi: 10.1186/1550-2783-10-5. PMID: 23360586; PMCID: PMC3577439.