How many times have you heard that you need to get your protein in after your workout? Maybe even that it has to be within 30 minutes. You may have even heard it called the ‘anabolic window’. Maybe you suffered from post workout protein anxiety when you’re unable to do so. Don’t want to lose those gains.
But never fear. While the concept of post workout protein and the ‘anabolic window’ was well popularised via forums, magazines and gym folklore, more recent research has been shifting focus toward overall levels of protein in 24 hour days.
An excellent study published by Brad Schoenfeld’s team[¹] wanted to look at this concept of the anabolic window and whether indeed it exists.
The study took two groups of trained men, put them all on a 10 week resistance training program and gave one group 25 grams of protein immediately before the workout, the other group 25 grams of protein immediately after. Both groups were given dietary instructions to maintain a calorie surplus of about 500 calories with total protein at 1.8 grams per kg bodyweight.
So to summarise thus far, you have two groups of men, both doing the same workout and eating the same diet for 10 weeks— just one group is having a protein shake before workouts, the other after.
To measure progress and results participants body composition (via DEXA), max strength and muscle thickness were measured at the beginning, middle and end of the 10 week program.
The findings? Both groups lost fat mass (they probably ended up in a calorie deficit) but there was no difference in the relative amount lost between the pre or post protein groups. Neither group gained significant muscle mass and likewise there was no significant difference between either group. As you would expect after 10 weeks of training, both groups got significantly stronger but again, no significant difference between the pre and post protein groups.
What does this mean? Well clearly in this study the concept of an anabolic window was not there — there was no difference in body composition between the group that took protein after the workout and the one that didn’t. In practical terms this means you can probably relax a little about downing a protein shake immediately after your workout.
What is undisputed however is the need to keep daily protein levels up and this is best done by consuming quality protein during the course of the day in the form of real food and supplements if required. Our recommendation based on the current state of the science is for 1.2–2.0 grams of protein per kg of body weight per day. The upper end of that range if you’re very active, the lower if you’re more sedentary.
A final point to note is while it might not be critical to consume a protein shake immediately after a workout it is an easy habit and if this helps your compliance in meeting your daily protein requirements then it is still a good thing. Just don’t stress if you miss it one time, your gains are safe.
[¹] ‘Pre- versus post-exercise protein intake has similar effects on muscular adaptations’, Schoenfeld et al, 2016 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5214805/