The main precursors of diabetes are: a. Hunger from time to time. When a normal person suddenly shows a great increase in appetite and prefers to eat sweets, it may be one of the initial symptoms of diabetes. Second, thirst. Thirst is a typical manifestation of the initial symptoms of diabetes. If a person who usually does not drink much water, drinks significantly more water in a period of time than before, it is possible that he or she has diabetes. Third, weight loss. When there is no exercise, no diet pills, nothing to do, weight loss suddenly, it is also possible that the initial symptoms of diabetes. This is because during the initial symptoms of diabetes, the glucose in the blood cannot be fully utilized and excreted from the urine, resulting in a sudden weight loss in the early stages of diabetes. Blurred vision. Elevated blood glucose can cause changes in the osmolarity of the lens, resulting in blurred vision due to dysfunction of the lens.