When we learn a workout “rule” early on in our fitness journey, it stays with us for years. For me, it was the advice to always eat protein within 30 minutes of finishing a workout. I’d heard that advice so many times from so many people that I never questioned the rush to sip chocolate milk or munch on some nuts when I didn’t have an appetite.
But recently, several sports dietitians have told me that 30 minutes is something of a myth. And yet, I’ve seen and heard it time and time again. So what’s the truth? Turns out, this nutrition advice is nuanced. “The reality is, there’s no one-size-fits-all term,” says Chad Kirksick, PhD, an associate professor of exercise science and sports scientist at Lindenwood University in Missouri.
Before you force yourself to down another protein shake as you leave the gym, there are some circumstances to consider.
Why you need protein after exercise
The main purpose of consuming protein after exercise is to take advantage of the “anabolic window” – the period of 30 to 60 minutes after exercise when your body is highly sensitive to the process of muscle protein synthesis and muscle mass building – and to do that, you need protein in your body.
“Your body is constantly making and breaking down protein, and exercise accelerates that cycle,” Dr. Kirksick explains. “Protein is made up of amino acids, and our bodies don’t store amino acids (like they do with carbohydrates and fats), so getting amino acids in the form of dietary protein can help replenish what’s lost.”
Eating protein (and carbs) after exercise also impacts your immune system. “The immune system is suppressed during training,” explains Michelle Arendt, R.D., director of Olympic Sports Performance Nutrition at the University of South Carolina. When you consume nutrients after exercise, your immune system gets a signal that it’s okay to start functioning normally again.
Side note: Carbohydrates also have an anabolic window. If you wait more than an hour after exercise to eat carbohydrates, it will take your muscles about 50 percent longer to replenish their energy store of glycogen, according to Bradley Schoenfeld, PhD, a professor of exercise science and researcher at Lehman College in New York. But this only matters if you’re an endurance athlete who works out multiple times a day. If you miss that window, your glycogen stores will generally return to normal within 24 hours, as long as you eat enough.
Arguments against instant protein intake
In 2013, Dr. Schoenfeld led a large meta-analysis showing that timing protein intake around a training session doesn’t have much of an effect on muscle building, a position he still holds today. “Based on what I’ve read in the literature, I think we can say with confidence that the benefit of the anabolic window is small,” he says. do not If you don’t eat protein, you’re missing out on big benefits.”
He says that our muscles remain sensitive to protein for a full 24 hours after exercise, so simply consuming protein in your regular diet (as experts recommend) can be effective.
“If you’re trying to stay healthy and you go to the gym before work and then have breakfast or exercise and then have dinner, 30 minutes isn’t that important,” says Catherine Black, PhD, an associate professor in the department of human nutrition at the University of Otago in New Zealand. “What’s more important is your overall protein intake for the day.” The American College of Sports Medicine recommends that active people eat 0.5 to 0.8 grams of protein per pound of body weight.
Kirksick adds that when it comes to building muscle, the actual training is the more important factor. “If you haven’t determined your exercise volume and total daily protein intake, I think the potential for further gains from that timing scenario is diminished,” he says. “One might argue that the effect is gone.”
Who can benefit from consuming protein post-workout?
While the anabolic window may be a bit overstated for those who hit the gym every day, for bodybuilders and elite athletes who put on back-to-back intense training sessions, the timing strategy could offer a small advantage. Dr. Shawn Fred says that those who may benefit from ingesting protein post-workout are “people who want to gain as much muscle as possible from their training.”
Arendt also points out that most athletes already don’t eat enough to meet their energy needs, so telling them to not eat protein after training would take away that opportunity, “which creates an even bigger deficit,” he says.
She has a similar view for menopausal and post-menopausal women, who believe that consuming enough protein evenly throughout the day is crucial for goals like muscle maintenance and overall health, explaining that as we age, our protein needs increase.
For now, it’s unclear whether women’s bodies respond differently to post-workout protein. “The studies that have been done so far aren’t as good and there aren’t enough of them to make any firm conclusions,” says Dr. Black. But noted exercise physiologist Stacey Sims, PhD, theorizes that eating toward the end of a workout may be more important for women because they bounce back faster after exercise and their hormonal state complicates the body’s response to protein.
The bottom line: There’s no harm in consuming protein immediately after training. Arendt acknowledges that, in general, there’s no downside. But unless you’re trying to land a WNBA contract or win an Ironman, you probably don’t need to stress about the timing. Even if you consume protein a little later than “optimal,” you’ll still get the nutrients your body needs.
