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.
Excessive insulin in the blood reduces your sensitivity to insulin and can cause diabetes, which is also linked to overweight and obesity. Exercise improves insulin sensitivity and reduces the reliance on insulin injections. Moreover, the effects of exercise on the endocrine system are also psychological.