There are some people who choose to take supplements after their exercise regiment. There are others who instead choose to eat regular food, without any powders, shakes, or bars. Regardless of your choice and the confidence you have in it, there is something all exercisers should be mindful of. The sooner you give your body nutrition after exercise, the better off your recovery will be.
A common recommendation is eat something, or supplement with something within 2 hours after exercise. This recommendation is fairly accurate. In his book "Exercise & Sport Nutrition," Richard Kreider cites research which shows that nutritional intake following exercise is still beneficial 2 hours after exercise. Athletes should also realize that delaying nutrition for 2 hours, as opposed to just one hour after exercise, can reduce the rate of muscle glycogen repletion by 50% (Kreider). This is especially important news for athletes who train multiple times in one day, or who will be training the following day. The sooner your muscles have recovered their glycogen stores, the sooner you will have more energy available to you for exercise.
Consider this: depending on how depleted an athletes muscles are, it can take 24 hours for complete muscle glycogen restoration (Krieder). Your body can use all the assistance you can manage to make sure this restoration happens quickly, and getting your body some nutrition within one hour after exercise is one way to do so. And of course, you need to continue to consume carbohydrate as time goes on after exercising, just like you normally would.
So the common recommendation of a 2 hour window after exercise remains true, but an even better approach is to consume nutrition sooner than that, preferably within one hour after exercise. Of course, if you are not able to eat within 2 hours make sure to eat as soon as you can. You will not have the same recovery benefit, but your body still needs the nutrition to recover. Just because you might have missed the optimum window of recovery doesn't mean you should not eat anything at all until the next meal.
Kreider, Richard B., Brian C. Leutholtz, Frank I. Katch, and Victor L. Katch. Exercise & Sport Nutrition: Principles, Promises, Science, & Recommendations : The Ultimate Training and Nutrition Guide to Optimal Health, Fitness, and Performance. Santa Barbara, CA: Fitness Technologies, 2009. Print.