If you’ve ever set foot in a gym, you’ve probably heard someone say “you’ve got 30 minutes after a workout to eat or drink your protein for optimal gainz.” You can find snippets all over the web that discuss this window of opportunity in great detail, even in major publications. The theory goes that for 30 to 60 minutes immediately following a workout, our bodies are in shock and our metabolism is increased, which, in turn, results in enhanced nutrient absorption and accelerated recovery. But does this post-workout anabolic window actually exist, or is it just a fabled myth to be written off to the realm of pseudo-science?
As a nutritionist, questions such as these plague my very existence. The science of nutrition is extremely fragile, extremely political, hotly debated, and is in it’s relative infancy as far as our understanding of nutrients and phytonutrients and their effect on our bodies goes. Working with athletes, especially, I have been asked this countless times. If only I had a nickel… This idea that the post-workout meal is the most important meal of the day is so ingrained in our society and our minds, that it makes me wonder what other “common knowledge” is out there in the fitness community that I should be doing research on (hint hint… stay tuned).
Admittedly, I was told this long ago and took this information as fact without ever having researched the science myself, until now. What I’ve found is, not surprisingly, conflicting evidence.
Most blogs or articles hinting at this anabolic window generically state “research shows…” but then don’t actually link to the research or say where the research comes from. In other words, they don’t back up their claim. For example, in a recent Runner’s World article, they state:
“Runners need to time protein intake to hit the 30-minute post-workout recovery window.”1)http://www.runnersworld.com/nutrition-for-runners/the-power-of-protein-timing
It’s almost like an after thought. Similarly, from Men’s Fitness:
“Research suggests there is a window of opportunity, which lasts up to one hour after a workout. In fact, some studies have showed that participants who consumed protein immediately after their workout versus a placebo gained ‘significantly’ more muscle size and strength than those who consumed it two hours removed from their workout.”2)http://www.mensfitness.com/training/pro-tips/fit-5-pre-and-post-workout-nutrition
Again, no source study. But that doesn’t mean that said research doesn’t exist. There are, indeed, several studies that shows that a post-workout meal does increase muscle hypertrophy. For example, the most often cited study, published in 2001, used elderly subjects with an average Body Mass Index (BMI) of 253)http://www.ncbi.nlm.nih.gov/pubmed/11507179. However, the elderly digest protein differently than younger adults4)http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761774/, and digest protein more slowly. This would imply that waiting a longer period after working out for your protein shake would be more beneficial, assuming the age groups were biologically similar.
Alternatively, a comprehensive study published on January 29th, 2013 in the Journal of International Society of Sports Nutrition5)http://www.jissn.com/content/10/1/5 concludes that, for protein in particular, the body of research has several limitations.
- First, while there is an abundance of acute data, “controlled, long-term trials that systematically compare the effects of various post-exercise timing schemes are lacking.” In other words, there is no consistency between studies (not repeated). Scientific theories become more sound the more you can repeat the same experiment and achieve the same results.
- Second, the majority of studies have been conducted on untrained individuals. Muscular hypertrophy occurs differently in those who already strength train vs. those are just starting out.
- Third, the methods used to measure muscular hypertrophy vary widely. There is no industry standard in this area.
Verdict: Fiction… There is no science that shows, decisively, that this post-workout anabolic window of opportunity exists due to the limited experiments that have been performed regarding the post-workout “window of opportunity” for enhancing muscle growth.
HOWEVER… there is no harm in feeding your body a healthy dose of protein and carbohydrates immediately following a workout. And who knows, maybe, one day, science will prove that it does exist, while you’ve been optimizing your gainz all along. I, for one, shall continue to eat (or drink) my protein and consume my complex carbohydrates after exercise, but is it the most important meal of the day? No, it is not. Nothing will replace breakfast, especially as it pertains to it’s benefits on exercise and muscle growth and retention; but that’s for another day.
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