BY JESSICA GIRDWAIN Men's Fitness
You probably heard one of the basic tenants of getting bigger and stronger: Eat protein within an hour after exercise to fuel muscle growth. It’s called protein timing, and the idea behind it is this: Resistance training increases amino acid delivery to muscles as well as absorption. Therefore, the sooner you consume protein post-exercise, the bigger the stimulation in muscle protein synthesis. In theory, proper protein timing leads to bigger long-term gains in strength and lean body mass.
But research doesn’t actually prove that it works—or doesn’t work, for that matter. “About half the long-term studies say protein timing has an effect and the other half doesn’t,” says Alan Aragon, M.S., Men’s Health nutrition advisor. The studies that do show a consistent benefit are all short-term, and many have limitations.
For example, Aragon cites one recent meta-analysis of 22 studies published in the American Journal of Clinical Nutrition. It found protein supplementation improved lean body mass and muscle strength. Because most of the studies asked participants to consume protein around exercise, researchers concluded that the meta-analysis found that timing does lead to bigger muscle gains. Aragon notes, though, that the average protein intake of the participants was low for an active person (about 0.5 grams per pound of body weight) and protein supplementation brought that intake up to maximal levels (about 0.8 grams per pound of body weight). “It may be just that consuming more protein overall is what helped—not that the supplement was timed with exercise. From the research, there’s no way to isolate that timing or total protein made the difference,” says Aragon. (For more must-have muscle tips, sign up for the Men’s Health Personal Trainer newsletter!)
Here are three truths you need to know about protein timing:
1. The “magic window” is longer than you think
Some experts say that you should consume protein 20 minutes post-exercise, while others claim it’s an hour. The reality: You’ve got longer. Studies show muscles’ elevated sensitivity to protein lasts at least 24 hours, says Aragon. In fact, one 2012 review study by McMaster University showed that muscle protein synthesis may continue for 24 to 48 hours post-workout. “The effect is higher immediately after exercise and diminishes over time, but that certainly doesn’t imply a magical window closes after an hour,” says Aragon. That means, theoretically you would want to eat protein right away—but because there’s not a huge post-exercise drop off in muscle protein synthesis, you don’t have to rush to pound a protein shake. Why? See our next point.
2. Total protein intake matters more
For the average active guy looking to be healthy and lose weight, protein timing won’t make a difference if you don’t meet other nutritional needs first, says the leading researcher and a big advocate of post-exercise feeding, Stuart Phillips, Ph.D., of McMaster University in Ontario. Not that timing isn't helpful, just that it’s not the most important factor in building muscle and weight loss. What is? Along with consistent workouts, you need to consume an ample amount of protein during the day.
Spacing out protein intake may maximize its effects: One of Phillips’ 2012 studies published in Nutrition & Metabolism found that consuming 20 grams of protein (roughly the amount in a container of Greek yogurt) every three hours four times a day was better at helping men build lean body mass than eating protein more often (10 grams of protein eight times a day) or less frequently (40 grams of protein twice a day). Moderate amounts may more effectively stimulate muscle protein synthesis, researchers note. “In addition to the muscle benefits, protein is remarkably satiating, so this will also help with weight loss,” says Phillips. The good news: Most of us eat three or four times a day anyway—just make sure your meals are well-rounded and include protein.
3. Eating before a workout works, too
Depending on the size of a meal, amino acid, glucose, and insulin levels in your blood peak anywhere from one to three hours after eating—your muscles’ “absorptive state” where they’re most receptive to protein. After that, it takes 3 to 6 hours for those blood levels to fall back down to baseline. That’s a big window. So if it’s more convenient, you can eat a protein-rich meal within 1 or 2 hours pre-workout and reap the benefits, notes Aragon. If your schedule doesn’t allow for eating pre-workout or you avoid it because it hurts your stomach, it’s not a big deal—just make sure you eat something after.
Though research is mixed, one study in Endocrinology and Metabolism found that consuming 20 grams of whey protein before exercise was just as effective as taking it one hour after exercise.
YOUR MAXIMUM MUSCLE PLAN
For general health and weight loss for active men, Aragon recommends consuming about 0.6 to 0.9 grams of protein per pound of body weight, erring on the higher side. (One caveat: Trained athletes cutting calories may need to consume more than 1 gram of protein per pound of body weight.) The benefits of eating more protein are great, he says, helping to preserve lean body mass (particularly important if you’re cutting calories to lose weight), raising metabolism, and increasing satiety.
For the guy trying to squeeze more from his workout, protein timing may help. An easy guideline for everyone? Eat 25 to 40 grams of protein within one to two hours pre- and post-workout. Basically, “time your workout between protein-rich meals and you’ll cover all your bases,” says Aragon. Some options: a scoop of whey protein powder mixed with water, 1 ½ cups Greek yogurt, one cup of cottage cheese, or 4 to 6 ounces of chicken or pork.