There is uncertainty about the optimal diet in the prevention and treatment of diabetes type 2. Earlier studies have generally focused on intakes of fat, protein, carbohydrate, fiber, fruit and vegetables. This study is based on another approach which compares foods that were available during human evolution with more recently introduced ones. The basic tenet from evolutionary biology is that if human physiology is less adapted to a relatively recently introduced diet based on agriculture, this could cause disturbances to human physiology and ultimately lead to diseases. Epidemiological studies indicates that diabetes mellitus type 2 is absent or near absent in populations eating a Palaeolithic ("Old Stone Age") diet which is free from food items produced in agriculture or the food industry. Our study hypothesis is that a Palaeolithic diet is better than the standard diabetes diet recommended today in treating diabetes type 2.