Carbohydrates are almost as important as protein in the post workout shake. Carbs cause insulin release, and there is nothing better to lower cortisol levels that insulin. Insulin has an antagonist relationship with cortisol, meaning when insulin levels are high coritisol levels must be low. Also, since insulin is a storing hormone it will shuttle the amino acids from the whey protein directly into the muscle tissue.
As for carb choices, the aforementioned bagel should be 100% whole wheat, not white. At all times during the day, in fact, choose whole-grain foods over refined ones, the only exception being immediately after a workout, when fast-digesting carbs reign supreme for boosting insulin and replenishing muscle glycogen stores (see Law 8). Keep carbs to less than 2g per pound of bodyweight per day.
It’s a little counterintuitive, but consuming calories after you’ve just burned them appears to be vital to fat-burning. Your muscles need a combo of protein and carbs to replenish energy stores and build new muscle. In one study, people who downed a 270-calorie shake with 24 grams of protein and 36 grams of carbs after their workout lost about four more pounds of fat and built more lean muscle than those who didn’t refuel post-exercise. Eating protein after a workout may help with lean muscle gains and could also help to prevent overeating later in the day, says Lesli Bonci, RD, a nutritionist and owner of Active Eating Advice. Find out what fitness instructors eat post-workout.
This may explain why the fat-burning effects of eating more protein were confirmed in a study published in the American Journal of Physiology. One group was fed a high-protein diet (just over 1 gram per pound of body weight per day) while the second group consumed an amount closer to the lower recommendation of the RDA (recommended dietary allowance). The group eating the higher-protein diet burned the most fat.