I'm sure you've read about it online before or perhaps heard some guys talking about it in the gym.
"You MUST get your post-workout whey protein shake in within half an hour of finishing your workout for maximum gains"
I've seen guys sprinting out of the gym to get their shaker out of the car after a workout to ensure they don't miss the window.
The importance of the anabolic window has been stressed for decades, but just because it's been discussed and practiced for so long does not mean it's actually legitimate.
Let's take a look and see if the anabolic window is legitimate or whether it's another one of those things that's been spread by word of mouth from gym-goer to gym-goer for decades (like many other training/dieting myths we've dispelled with science).
What ACTUALLY Is This Supposed Anabolic Window?
Regardless of whether the anabolic window is real or not what is the supposed explaination of this crucial 30 minute post-workout period?
Allow me to explain...
When we lift weights the goal is to damage our muscle fibers so they repair themselves, coming back bigger and stronger.
While we're lifting weights we're expending our glycogen stores (your glycogen stores are carbohydrates stored by your body for quick energy).
This is 100% correct.
Now here's the part we're investigating...
It's claimed by ingesting 30~ grams of protein and a bunch of simple carbohydrates (think dextrose) within 30 minutes of putting down your weights that we can spike muscle protein synthesis and completely replenish our glycogen stores - resulting in a period of unprecedented growth.
What Do Supplement Companies Say About The Anabolic Window?
Supplement companies will use technical terms and share random numbers with you to try and convince you that the anabolic window is real.
Then again, supplement companies will tell you whatever they need to in order to get you to buy their product.
"Replenish your glycogen stores 38% faster with our hydrolized whey protein!"
"The ultimate fast digesting protein, specifically designed to maximize gains during your anabolic window"
Every other tub of whey protein has a similiar claim on the side of the tub, take note next time you're in your local supplement store.
Here's the thing... why would you pay hundreds of dollars for a small tub of 'hydrolized' whey protein that is said to be super fast absorbing after your workout when you can get the exact same benefit by eating a steak or a chicken breast hours after your workout that cost a fraction of the cost per serve?
Regardless of what science says the supplement industry would never admit that the anabolic window isn't real.
That'd be shooting themselves in the foot, that would be destroying their sales.
The more studies that're performed the more these supplement companies are getting outed.
What Does Science Say About The Anabolic Window?
In short science does NOT back the claims the supplement industry and bros in the gym make regarding the anabolic window, let's take a look at some points and conclusions drawn by a number of reputable studies on the anabolic window, protein synthesis and whether our glycogen stores need to be refilled immediately after a workout...
"The major finding from this study is that delaying the ingestion of HGI foods by 2 h has no effect on muscle glycogen storage at 8 and 24 h post-exercise respectively, providing that sufficient carbohydrate is ingested during the recovery period. This finding indicates that, despite glycogen storage being most rapid immediately following exercise(15), athletes need not consume carbohydrates immediately after training or competition to restore glycogen to high levels providing that they ingest sufficient carbohydrates in the 6 h post-exercise and are not required to exercise again within 8 h"
"For the goal of maximizing rates of muscle gain, these findings support the broader objective of meeting total daily carbohydrate need instead of specifically timing its constituent doses. Collectively, these data indicate an increased potential for dietary flexibility while maintaining the pursuit of optimal timing."
My Personal Experience
I must admit, the first year or two of training I religiously brought a protein shaker with one and a half scoops of whey protein concentrate and one scoop of dextrose (simple carbohydrates) to the gym ready to devour straight after my workout. Hell, I even premixed it at home so I didn't need to go to the water fountain at the gym... that's efficiency.
Then the more I read the more I realized I probably didn't need to be doing that.
So I stopped.
That was 6~ years ago.
I've continued to make size and strength gains ever since.
As the nutrient timing revisited study above mentions it's hitting your protein and carbohydrate intake goals over a 24 hour period that're going to make the biggest difference in terms of cultivating new muscle mass and strength, not some 30 minute 'window' after your workout.