Pre- and Post-Workout
For consistent, long-term lifters, protein synthesis will peak much earlier—about four hours post-workout—and return to baseline levels faster. So the protein you eat immediately before and after your workout becomes more important.
In a 2012 study in the American Journal of Clinical Nutrition, the researchers compiled data from multiple studies looking at protein and strength training. They found that those who used protein supplements gained 2 extra pounds of muscle over 12 weeks, compared to those who didn’t. For experienced lifters, they concluded that pre- and/or post-workout protein supplements are required to achieve maximum results.
The “window of opportunity,” when your muscles are most receptive to protein, appears to be about four to six hours, according to a 2013 study in the Journal of the International Society of Sports Nutrition. Ideally, you want a protein-rich meal two to three hours before training, and another within an hour or two after you finish.
Those who work out in the morning before breakfast have a narrower window. Protein synthesis slows down by about 15 to 30 percent while you’re sleeping, according to Dietary Protein and Resistance Exercise, a textbook published in 2012. So if you work out before eating, you want a post-workout meal as soon as possible.
Best Protein Sources
Different types of food contain different combinations of amino acids—the building blocks of protein. Leucine is by far the most important of the 20 amino acids for creating muscle. It takes an estimated 2 to 3 grams of leucine to get the maximum anabolic effect from a meal.
Just about any normal-size serving of meat or poultry will contain at least 2 grams of leucine. (A serving size is roughly the size of your palm.) Three eggs, two glasses of milk, a piece of fish, or a cup of yogurt will give you about 1.5 grams. A cup of cottage cheese or scoop of whey protein (25 grams) will give you close to 3 grams.
Among plant foods, soy has the most leucine. A cup of soybeans has 2.3 grams. Beans and lentils are the next-best sources, with 1.2 to 1.4 grams per cup. A quarter-cup serving of nuts or flaxseeds will have about 0.5 grams.