How important is having protein after your workout? It turns out not much––but there’s a bit more to it than that. Here’s what you need to know about post-workout protein.
Many years ago, a fresh-faced overenthusiastic Aadam was just starting his personal training career. He was cocky, and he thought he knew it all. Which is just a diplomatic way of saying he was an arrogant little shit who didn’t know as much as he thought.
One of the things he was adamant about was the importance of post-workout protein. So adamant, in fact, he would force protein shakes down his clients’ gullet as soon as they finished their workout.
If you had asked younger me why, I’d have scoffed at your apparent ignorance and launched into a needlessly long rant where I’d explain that:
- After a workout, your muscles are being broken down and consuming protein as soon as possible provides your body with the amino acids it needs to start the repair and growth process.
- There’s a short window of time––informally called ‘the anabolic window’––after the workout for you to consume protein to maximise your gains from that session. If you don’t take advantage of this window well, you just done fucked up, and all your hard work was for nothing.
As it turns out, younger me wasn’t entirely wrong. He just missed a lot of nuance and context. That nuance and context are what we’ll be covering in this article. So let’s begin.
Does post-workout protein prevent muscle breakdown?
To understand if post-workout protein prevents muscle breakdown, you first need to understand two terms: muscle protein synthesis and muscle protein breakdown. Don’t worry, they’re not as scary as they sound.
Muscle protein synthesis
The protein you consume from your diet is broken down into amino acids in the body.
These amino acids are then used to repair and grow new muscle tissue (which is why protein is colloquially referred to as “the building block of muscle”).
This process is called “muscle protein synthesis” (or MPS for short)––i.e., the synthesis of new muscle.
Muscle protein breakdown
Opposing muscle protein synthesis is muscle protein breakdown (or MPB) and, as the name suggests, is when muscle is broken down into amino acids.
Despite being two different processes, they’re always occurring to some extent throughout the day.
For instance, if you skip breakfast and eat your first meal a few hours after waking, muscle protein breakdown remains elevated until your first (protein-rich) meal. At which point, muscle protein synthesis exceeds muscle protein breakdown. As the time between your first meal and second meal lapses, muscle protein breakdown will slowly start to increase until you eat again, at which point muscle protein synthesis increases. And on and on it goes.
Interestingly, and somewhat counterintuitively, strength training increases both muscle protein synthesis and muscle protein breakdown. Though, muscle protein breakdown outpaces muscle protein synthesis until you eat protein. 1
You might be thinking, if weight training increases muscle breakdown and eating protein increases muscle protein synthesis, then, uh, why not eat protein as soon as possible to stop my muscles from being cannibalised?
Ok, this is awkward. Remember when I said you need to understand two terms? Well, I lied. There’s one more term I need to explain: Net protein balance.
Net protein balance is exactly what it sounds like: the balance between muscle protein breakdown and muscle protein synthesis.
If the muscle protein breakdown rate exceeds the rate of muscle protein synthesis for extended periods, you’re in a negative protein balance, and you’ll lose muscle.
If the muscle synthesis rate exceeds the rate of muscle breakdown for an extended period––you’re in positive protein balance, and you’ll maintain or build muscle.
This is why you don’t need to worry about the short-term breakdown or synthesis of muscle, like post-workout. You need to be more focused on staying in a positive protein balance over the long-term.
For instance, whey protein––a “fast-digesting” protein source––is estimated to have an absorption rate of 10g/hour. So if you had 30g of whey protein before training and your workout lasted an hour, you’d have amino acids in your bloodstream for up to 2 hours post-workout. 2
But in reality, the majority of your food intake will come from whole food protein sources as part of a mixed meal, extending the amount of time amino acids are available in the bloodstream for up to 5-6 hours.3 4
So if you had 30g of protein as part of a mixed meal an hour or two before training, and your workout is an hour-long, you’d still have amino acids in your bloodstream for up to two to three hours post-workout.
Looking at all of this, we can safely assume two things. First, total protein intake is more important than post-workout protein. Second, distributing your total protein intake over 3-4 meals per day will ensure your body always has amino acids available for repair and growth.
But what about the purported ‘anabolic window’? Are there unique benefits exclusive from total protein intake to consuming protein as quickly as possible after a workout? Let’s talk about that.
Protein timing and the anabolic window
In the early 2000s, a few studies suggested the post-workout period is when the trained muscles were most sensitive to take in nutrients. And the further away you got from consuming nutrients in this window, the less effective post-workout nutrition became.
Not just that, but this “anabolic window of opportunity” only lasts 45-60 mins on completion of the workout. 5 6
That was until the publication of a 2013 meta-analysis that challenged this long-held dogma.
The researchers analysed 43 randomised controlled trials to determine the effect of protein timing on muscle and strength gains.
On their first analysis, the researchers found that, indeed, consuming protein within an hour of completing a resistance exercise session did lead to a small-to-moderate effect on muscle gain compared to delaying post-workout protein by two hours.
But the researchers weren’t done yet. They then conducted a sub-analysis and found the benefit to protein timing wasn’t because of some ‘anabolic window’ magic but something far less exciting: the post-workout protein groups had a higher total protein intake compared to the groups who didn’t have protein post-workout.
When researchers looked at studies with matched protein intake between groups, there was no benefit to post-workout protein.
That said, it’s worth pointing out only three studies matched protein intake between groups.
Of these three studies, only two used trained individuals. Aa One study showed a significant benefit to protein timing, and one showed no significant difference.
However, the study that found a benefit gave participants a shake pre– and post-workout, making it hard to conclude whether the benefit was due to protein timing or total protein intake. Additionally, the shakes included creatine which most likely influenced the results.
More recently, Schoenfeld et al. conducted a randomised control trial comparing pre– versus post-exercise protein timing in 21 men with more than a year of resistance training experience.
The participants were split into two groups: The first group consumed 25g of whey protein before starting a full-body strength training session. Upon completing the session, they were instructed to avoid eating anything for at least three hours post-workout.
The second group––the post-workout protein group––was instructed to avoid eating for at least three hours before starting the workout and consumed 25g of whey protein immediately after the training session.
At the end of the 10-week study, there was no difference in strength or muscle gain between groups (though the post-workout protein group showed a small but non-significant increase in bicep growth).
The researchers noted some of the limitations of their study, including the use of self-reported diet records––i.e., people suck at reporting how much they actually ate.
Further, despite the researchers instructing participants to maintain a ~500kcal surplus, they were in an average deficit of ~350kcal by the end of the study.
A calorie deficit makes muscle growth harder, especially in trained individuals. So while this study shows that both pre– and post-workout protein are similarly effective at retaining muscle when dieting, it doesn’t tell us how protein timing would affect muscle gain in a surplus. Aa
What to make of all of this?
The most important takeaway is total protein intake matters more than protein timing. Ensure you’re consuming enough protein every day to maintain a positive protein balance. This will ensure your body always has enough amino acids to use for repair and growth.
Second, the ‘anabolic window’ isn’t as short as once believed. Your body is primed to take in and use nutrients anywhere up to 24 hours on completion of a workout. 9 10 11 Meaning, you’re not leaving your gains on the table if you don’t immediately chow down some protein.
With that said, I don’t want you to read this and think protein-timing doesn’t matter at all—context matters. And protein timing becomes more important in some instances. As such, let’s wrap this all up with some general recommendations.
Post-workout protein TL;DR
- Avoid extremes. The ‘anabolic window’ might not be as short as once believed, but this isn’t a reason to abuse it. I still recommend my clients have some protein before and after training to err on the side of caution. If nothing else, it’s a convenient way to hit your protein targets, especially for those who are busy and can’t always sit down to eat a meal. Additionally, if you train early in the morning, a post-workout shake can help reduce hunger.
- Spread your protein intake evenly across multiple meals. How many meals you eat will come down to your personal preference, but anywhere between 3-5 meals per day will suffice. This, along with consuming enough protein every day, is more than enough for 99.95% of you reading this. And yes, I totally made that percentage up.
- If you’ve consumed protein 1-3 hours before your workout, post-workout protein becomes less critical. As long as you have some protein within 1-3 hours of finishing the workout, you’ll be fine.
- If you train fasted in the morning, post-workout protein becomes more important. In this case, aim to consume some protein as soon as it makes sense for you (ideally within 0.5-2 hours of completing the workout). Though the sooner, the better.
- If you haven’t eaten 4-5+ hours before training, have some protein (like whey) 30-60 mins before you work out. You can then push the post-workout meal back by a few hours.
Thanks for reading. If you enjoyed this, you’d love Physiqonomics Weekly
95% of my new content is only being sent out to my email list. One email every Thursday filled with actionable, evidence-based, fitness advice to help you with your goals. If you enjoy and find value in the website content, you’ll love my emails. You can learn more and subscribe for free here.