If I understand, you are correct that anthropology can have a lot of valuable insight into the development of diabetes and its relationship with changing human nutrition. Evolutionary medicine, informed by evolutionary anthropological thinking, can be a very important tool for modern medicine. I am involved with a project run by Karen Kramer of the Univ of Utah (USA) that has identified the first instances of diabetes diagnoses among Maya maize agriculturalists in Mexico associated with the recent availability of market foods, especially soda. If you search online for "evolutionary medicine anthropology" several textbooks and more advanced literature can be identified that will give you a start at looking at this perspective if you have not already found some of the anthropology research on this issue.