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.
First, foods from plants contain less total and saturated fat, resulting in reduced caloric intake, weight loss, and improved A1C levels. Second, independent of weight loss, a low-fat, plant-based diet improves insulin sensitivity, presumably by reducing intramyocellular lipid accumulation. As insulin sensitivity improves, carbohydrate tolerance increases. Third, participants in the diabetes studies by Barnard et al.