When training with teammates and loved ones, I’ve often been the one at the end of the workout to emphatically state, “Go home and eat. Make sure you get protein in your system in the next 45 minutes or so. Your muscles will be repairing themselves and you want to provide them with a fertile environment with fuel to do so.”
I’m not the only one. This is a popular narrative, and I’ve had it drummed into my head for nearly 20 years. Gyms and media outlets across the country have always made these suggestions. Here are some of the catchphrases commonly thrown out:
- “You need to feed your muscles”
- “You don’t want your muscles to eat themselves, do you?
- “20 grams of protein 20 minutes before and 20 minutes after your workout”
If you’ve been following the blog, you know that I preach challenging our assumptions. A statement beginning with “Everyone knows that you have to…” is a good time to take a look at the facts.
Protein timing is a popular dietary strategy designed to optimize the adaptive response to exercise. The strategy involves consuming protein in and around a training session in an effort to facilitate muscular repair and remodeling, and thereby enhance post-exercise strength- and hypertrophy-related adaptations. Despite the apparent biological plausibility of the strategy, however, the effectiveness of protein timing in chronic training studies has been decidedly mixed.
Our muscles certainly need protein in order to repair themselves efficiently and grow bigger and stronger. The timing advice, however, may have taken us off course.
The study conducted by the Journal of the International Society of Sports Nutrition was no small undertaking. They included over 500 subjects in an attempt to find some conclusive evidence that would either debunk or confirm that we the athletes need protein in a specific time period prior to and after our training sessions.
The strength analysis comprised 478 subjects and 96 ESs, nested within 41 treatment or control groups and 20 studies. The hypertrophy analysis comprised 525 subjects and 132 ESs, nested with 47 treatment or control groups and 23 studies. A simple pooled analysis of protein timing without controlling for covariates showed a small to moderate effect on muscle hypertrophy with no significant effect found on muscle strength.
Basically, in the simple pool analysis, the study showed at least some possibility that timing of protein intake is meaningful. But as the experiment unfolded and included more data, the popular theory began to look more like a myth.
In the full meta-regression model controlling for all covariates, however, no significant differences were found between treatment and control for strength or hypertrophy. The reduced model was not significantly different from the full model for either strength or hypertrophy. With respect to hypertrophy, total protein intake was the strongest predictor of ES magnitude. These results refute the commonly held belief that the timing of protein intake in and around a training session is critical to muscular adaptations and indicate that consuming adequate protein in combination with resistance exercise is the key factor for maximizing muscle protein accretion.
The most important thing to deduce here is that our muscles indeed require protein to grow, get stronger and stay healthy. Here’s the good news: we no longer need to risk that speeding ticket trying to get home and bite into that steak. We can spend the saved cash to upgrade to grass-fed and organic.