The Anabolic Window: Fact or Fiction?
Introduction:
Are you still clinging to the belief that protein consumption immediately after your workout is the key to enhancing your muscle strength and size? Well, it's time to reconsider your post-workout nutrition strategy. Recent studies have challenged the importance of protein timing around workouts, indicating that the anabolic window concept may not be as crucial as previously thought.
This article will delve into the science behind protein timing and provide evidence-based guidelines to help you optimize your protein intake for maximal muscle protein synthesis and growth, specifically, it’ll answer these 4 questions:
What is the "anabolic window" concept, and how has it been challenged by recent studies?
What is the recommended protein intake before and after exercise, and how long before and after should it be consumed?
How much protein is needed to stimulate muscle protein synthesis after a workout?
How important is the timing of protein intake in relation to exercise, and what should be the main concern when it comes to protein consumption?
TLDR: Think of the anabolic window like a grand bay window, not a tiny porthole. It's likely bigger than you think, giving you more time to get in the protein you need to stimulate muscle protein synthesis after a workout.
What is the Anabolic window?
If you're into fitness or have been researching muscle growth, you may have heard of the "anabolic window" concept.
This theory suggests that consuming protein immediately after a workout can enhance strength and hypertrophy. If you haven’t heard of it before, think of it as pressure to eat/drink protein as soon as possible after your workout to reap as many adaptions to that workout as possible. Read below to understand the ‘pressure’ surrounding this concept was:
Personal anecdote:
When I first got into training over 10 years ago, I believed that I had to consume a protein shake after every workout to make it effective. One day, while finishing up training with my dad, I asked him to stop at the nearest petrol garage to buy a protein shake, otherwise the workout would be ‘wasted’. However, I was disappointed to find out that they didn't have any. In a moment of panic, I spotted a 4 pint carton of semi-skimmed milk and bought it, hoping it would suffice.
Looking back, I realize that getting a protein shake after a workout isn't as critical as I once believed, and I hope this article helps to dispel this myth.
Since then, studies have questioned the importance of protein timing around your workout, and the concept has become somewhat controversial in recent years.
Research review and protein recommendations:
One 2019 evaluated the effect of protein timing on lean body mass and strength improvements in untrained post-menopausal women. The study divided 34 participants into the protein-carb or carb-protein groups, and both groups consumed roughly the same amounts of protein each day, with little dietary protein consumed just before and after workouts. For the course of the 8-week trial, the participants engaged in a full-body exercise regimen three times each week. Both groups experienced similar gains in strength and lean mass, indicating that eating protein right after working out may not provide any significant benefits for these outcomes.
So, what does this mean for protein timing and muscle growth?
Aragon & Schoenfeld 2013 suggested that a simple guideline for protein intake is to consume high-quality protein at a dose of 0.4-0.5 grams per kilogram of lean body mass (LBM) both before and after exercise.
How long ‘before and after’ you may ask?
They recommended that pre- and post-exercise meals should be consumed within 3-4 hours of each other, especially for resistance training bouts lasting 45-90 minutes. However, if a particularly large mixed-meal with sufficient protein is consumed, the interval between meals could be lengthened to 5-6 hours.
This guideline is relatively fail-safe and supported by current evidence, which indicates that a maximal acute anabolic effect is achieved with a protein intake of 20-40 grams.
Furthermore, while the timing of protein feedings in proximity to the lifting bout probably isn't absolutely critical, muscle protein synthesis is elevated for 24-72 hours after resistance training. There is a limit to which we can stimulate protein synthesis in a single meal, and protein synthesis is transiently elevated in response to feeding before returning to baseline. Therefore, hitting your total protein target should be your main concern, regardless of frequency and meal timing.
To maximize anabolism, aim to consume 0.4g/kg/meal across at least 4 meals to reach >1.6g/kg per day. However, merely hitting your total protein target is the main priority. When it comes to pre/post workout nutrition, a balanced, full meal consisting of carbs and protein 2-4 hours before and after your workout is recommended, with a target of 0.2-0.25g/lb for both protein and carbs.
If you're short on time, liquid or semi-liquid protein and carbs for easy digestion 30-60 minutes before and after your workout can also be effective.
Personalisation and context:
It's important to note that protein intake should be adjusted to individual needs and goals. Adequate protein intake is necessary to support muscle protein synthesis, and protein timing may be more important for athletes with high training volumes and frequencies. However, as mentioned earlier, hitting your total protein target should be your main concern, regardless of frequency and meal timing.
Remember, the apparent immediacy of protein post-workout is dictated by the previous meal's time from the workout and protein content. If you had a meal with 35g of protein just two hours before training, the 'need' to consume another 35g within the 'anabolic window' of 1 hour appears unnecessary, as you'll likely still be digesting the previous meal.
So if you eat within 2 hours of training, the importance of eating again after training to spike muscle protein synthesis and anabolic adaption is decreased compared to if you had carried out that session fasted.
Conclusion:
In conclusion, while the "anabolic window" concept may have once been widely accepted, current evidence suggests that protein timing immediately post-workout may not be as critical for enhancing strength and hypertrophy as initially thought. However, consuming high-quality protein at a dose of 0.4-0.5 grams per kilogram of lean body mass both before and after exercise can be a fail-safe guideline for optimizing protein intake.
Ultimately, hitting your total protein target should be the main concern, regardless of meal timing.
It's important to keep in mind that individual needs and goals should be taken into account when it comes to protein intake and timing, and consulting with a professional can provide personalized recommendations for optimal nutrition to support your fitness goals.
Sources:
de Branco, F. M. S., Carneiro, M. A. S., Rossato, L. T., Nahas, P. C., Teixeira, K. R. C., de Oliveira, G. N., Jr, Orsatti, F. L., & de Oliveira, E. P. (2020). Protein timing has no effect on lean mass, strength and functional capacity gains induced by resistance exercise in postmenopausal women: A randomized clinical trial. Clinical nutrition (Edinburgh, Scotland), 39(1), 57–66. https://doi.org/10.1016/j.clnu.2019.01.008
Aragon, A.A., Schoenfeld, B.J. Nutrient timing revisited: is there a post-exercise anabolic window?. J Int Soc Sports Nutr 10, 5 (2013). https://doi.org/10.1186/1550-2783-10-5