The Truth About Nutrient Timing

When I first started lifting weights back in the 90s, I had a very interesting habit.

At the time, I was living in my parent’s house (I was still a teenager) and I would train in our basement. My workouts were absolute crap. A combination of bench presses, more bench presses, and curls. For good measure, I’d throw in some lunges and calf raises. To no one’s surprise, I was a solid 130 pounds.

If you would have told me back then that I’d be coaching people, I would have laughed at myself.

The specific timing of your post-workout meal ultimately depends on when you eat prior to training.

But my weird habit wasn’t the workout; it was my post-workout routine. After I’d finish I’d rush upstairs, grab the jar of protein powder I’d stashed in my room (I didn’t want my parents to know I was taking protein powders), and I’d mix up the following shake and down immediately:

• 1 scoop of chocolate protein
• 1 cup of milk
• 3-4 cubes of ice
• Peanut butter (more than necessary)
• Banana
• Honey (not really necessary)
• Frosted Flakes (lots of them…I believe I got this from Muscle Media)

If I were to do the macros, I’d say I easily surpassed 100 grams of sugar in this shake. In some ways it’s shocking I didn’t become heavier, but at the time I wasn’t really eating much, and I certainly qualified as skinny-fat, soft, non-muscular. Feel free to add in whatever adjective you want. One hundred and thirty pounds is not a lot of weight.

While it’s funny to think back about that shake now (which was probably the best-tasting protein shake I’ve ever had in my life), there was reasoning (albeit faulty) to my culinary madness.

I’d read enough bodybuilding magazines that I “knew” had about 30 minutes to take advantage of my “anabolic window.” I need carbs–lots of them–to replenish the glycogen lost during my workout, and there was no need to fear the sugar.

Fast forward 20 years and while I laugh at my drink, the “science” of post-workout nutrition has changed dramatically–but the behaviors of most have not.

Many still believe that you need to down a shake within 30 to 60 minutes after your workout or else your body might go catabolic. Or there’s the prevailing belief that your workouts are so carb depleting that you must refill your carb stores…and then some.

Is there really an “anabolic window” after your workout? That’s the question Alan Aragon and Brad Schoenfeld recently asked in a thorough review (a meta-analysis) of the research published on post-workout meals and the perceived benefits. In all honesty, I knew about this paper going way back, and it was a big motivation for us launching The Muscle Lab.

I spoke with Alan and Brad about post-workout nutrition, their study, and what you really should be eating (and when) after you finish training.

Why We Thought Nutrient Timing Was Important

AB: Your study was a pretty big deal, but probably needs more attention in the mainstream. To catch people up to speed, can you tell me: What was the established “truth” that we thought we knew about protein timing? In other words, why did we think the timing was important and what benefit did we believe was accomplished by eating within the “anabolic window.”

Alan: The conventional wisdom was that there was a quick closing “anabolic window of opportunity” after the training bout. This had its origins in research in the late 1980s showing that a delay in carbohydrate consumption resulted in less glycogen resynthesis in the few hours following the bout. In light of this, fast-acting carbs ingested ASAP became the popular mantra.

However, subsequent research showed that complete glycogen resynthesis after depletion occurred within the same day (regardless of adjacent macronutrient variation, as long as total carbs were matched), so the applicability of the quickie-carb tactic turns out to be limited to a fringe population of athletes who must compete with the same glycogen-depleted muscles multiple times in the same day.

Subsequent research included protein and/or amino acids to the peri-workout period and found beneficial effects on muscle protein synthesis. However, this research shared similar limitations as the carb research in the sense that it only looked at the short-term, and it examined effects in over-night-fasted subjects, minus a pre-workout meal (let alone a protein-rich pre-workout meal).

Hence, the “anabolic window” concept gained momentum. However, this momentum ran into several snags as chronic (long-term) trials examining timing effects on hypertrophy and/or strength failed to consistently corroborate the promise seen in the acute (short-term) studies.

What We Know About Post-Workout Nutrient Timing

AB: What did you actually find in your study?

Brad: This was a complex analysis. We first performed a basic meta-analysis where the effects of protein timing on strength and hypertrophy were compared without adjusting for any confounding issues. The results showed that timing had no effect on strength, but a relatively small yet significant effect was found for hypertrophy.

This initially led us to believe that we had confirmed the presence of a narrow “anabolic window of opportunity.” We then proceeded to perform a sophisticated statistical technique called regression, where we analyzed different variables (i.e. covariates) in isolation to see if they affected the outcome. This produced the most interesting finding of all: the quantity of protein consumed explained virtually all the variance in results!

Specifically, a majority of studies did not match protein intake between groups: the experimental group consumed substantially more protein than the controls. Thus, the average protein consumption in the control groups was well below what is deemed necessary to maximize protein synthesis associated with resistance training.

Only a few studies actually endeavored to match intake. We did a sub-analysis of these studies. No effects were found on protein timing (and this was in spite of having to toss out a study that showed no effect because we weren’t able to obtain sufficient data for analysis).

Why There is No Extreme Urgency for Your Post Workout Meal

AB: Why isn’t timing as important as we thought? How was this thought perpetuated for so long?

Alan: Timing is still important, but indeed the strong urgency of timing implied by the earlier research has not been substantiated. While acute response provides interesting clues and hypotheses, it’s the chronic adaptations that ultimately matter. And thus far, chronic trials have collectively failed to strongly support the idea that muscular adaptations are compromised if there is a short delay in providing protein in the immediate period surrounding the training bout.

Furthermore, recent research has also repeatedly failed to show an enhancement of the anabolic response to training when carbohydrate (even substantial amounts of fast-acting, high-glycemic carbs) is co-ingested with sufficient protein, compared to protein alone.

In answering the question of how this dogma has been perpetuated so long, I’d say there are two main reasons. The first one is that people by nature are resistant to modifying, let alone completely overhauling their beliefs – especially when they have been preaching them as a matter of their careers.

True scientists do not hesitate to change their long-held stance on any given topic if the weight of the evidence warrants it. Unfortunately, this is just not the case with most people, including those in the academic sphere. The second reason for the perpetuation of the traditional wisdom is that the tide-shifting research is relatively new.

The New Rules of Nutrient Timing

AB: Based on the meta-analysis, is there any benefit to timing meals around your workouts?  

Alan: It’s intuitively implicit that timing nutrition around training is a good idea from both a fueling for performance and a recovery standpoint. However, our analysis did not detect any significant benefit of timing protein within the “magic hour” either pre- and/or post-exercise. It’s apparent that there is more leeway than this for optimizing gains in size and strength – which is a welcome finding from the standpoint of flexibility, practicality, and convenience.

AB: From your research, what are the most important takeaways? What can someone who trains use from this to apply to their goals? And does it differ based on muscle building vs. fat loss?

Brad: The primary takeaway from the research is that you don’t need to worry about slamming a protein shake the moment you finish training. It’s okay to chill out for a bit, do what you need to do, and then consume your nutrients.

We estimate that there is approximately a 4 to 6-hour window in and around the workout. The specific timing ultimately depends on when you have a meal prior to training.

Thus, the closer your meal to the training bout, the longer the window following the session. Now there certainly is nothing wrong with consuming nutrients immediately after training. And the limitations of current research leave open the possibility that there may be a small but significant that could be meaningful if your goal is absolute maximization of muscle mass.