You don’t have to dig too deep into the internet before you will come across researchers and bro science experts alike referencing a supposed sweet spot called the “anabolic window”. This anabolic window refers to the maximal window of opportunity for the protein and carbohydrates we eat to best enhance body composition and future athletic performance. This limited time window is thought to exist immediately after training and common knowledge dictates that it must be followed in order to optimize training-related muscular adaptations. Current thinking is that you won’t build muscle if you don’t eat your protein and carbohydrate packed post-workout snack within 30 to 60 minutes following your workout.

This idea of the anabolic window has been researched for almost three decades. In fact, the post-exercise time period is thought to be the most important moment in nutrient timing. After intense training, our bodies are depleted and looking for fuel to rebuild to be bigger and better than before.

Carbohydrates and protein are the fuel our body needs after training. Carbohydrates are needed to replete glycogen stores, which are the stores of carbohydrates found in the body that are used to fuel physical activity. Protein is needed to halt muscle breakdown and switch gears into muscle building. Furthermore, this combination of protein and carbohydrate intake spike our insulin levels. Insulin is considered an anabolic hormone that helps our body stop the breakdown of muscle post-exercise and possibly stimulate muscle building.

Let’s Talk Timing

The anabolic window theory claims that in order to maximize muscle building you must ingest the above mentioned post workout fuel during this magical time window. Some research suggests that the anabolic window exists within one to two hours, while other research indicates that this window can exist for up to four to six hours. After years of trying to figure out exactly when the anabolic window opens, the research is still inconsistent.

Here’s what we do know. After training, your muscles are sensitive and ready to absorb the much needed nutrients. This muscle sensitivity can last up to 24 and 48 hours after exercise. So maybe this “anabolic window” is actually more like an anabolic barn door. It isn’t the end of the world if you can’t get your post-workout snack in within an hour. Your body can reap the benefits for hours and hours to come.

Yes, it’s true that your post-workout snack should be consumed sooner rather than later, but it’s also true that your meal and snack patterns continue to matter following that initial post-workout snack. Your workout has made your muscles sensitive to the absorption of the nutrients we get from food and supplements for up to 48 hours, so being consistent with your intake of high-quality nutritious foods has just as much benefit as getting fuel in during the anabolic window.

The Take-Away

The anabolic window is actually more like anabolic barn door. Food consumption for 24 to 48 hours following exercise can enhance body composition and future athletic performance. Post-workout snacks should be consumed at your earliest convenience since your muscle are needing that fuel following exercise, but the idea that it only matters for hour after exercise is false. To optimize training-related muscular adaptations, we need to think about the bigger picture and be consistent with healthy, nutritious meals and snacks to keep reaping the benefits of hard training.

Sources:
https://jissn.biomedcentral.com/articles/10.1186/1550-2783-10-53
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3577439/
https://www.ncbi.nlm.nih.gov/pubmed/16705065