Proteins are necessary for tissue repair and for the construction of new tissue. Every cell needs protein to maintain its life. Protein is also the primary substance used to replace worn out or dead cells. Your muscles, hair, nails, skin, and eyes are made of protein.
Taking supplemental chromium has been shown repeatedly to improve insulin sensitivity and glucose tolerance, even to the point of reversing type II diabetes in many people (1). Thus, as my old clinical nutrition professor pointed out, apparently a chromium deficiency can actually lead to type II diabetes.
This suggests that you don't have to starve yourself after exercise to still reap some of the important health benefits. Enhanced insulin sensitivity means that it is easier for your body to take up sugar from your bloodstream into tissues like muscles, where it can be stored or used as fuel.