Generally, the peak blood glucose will arrive at 0.5-1h after meal for ordinary people, and 1-2h for diabetic patients. However, due to differences in individual physique and the type of food eaten at each meal, the peak value will change accordingly and the time is not fixed. After the general population eats, glucose enters the body and insulin starts to be secreted, the postprandial blood glucose usually peaks at 0.5-1h, then gradually declines and returns to fasting state around 3h; the time of peak blood glucose in diabetic patients is not certain, generally appears at 1h after meal, and the peak in some patients is shifted later and may be at 2h after meal, which is caused by the body’s insulin not being secreted on demand. After a meal, insulin response is slower in diabetic patients, and the peak of blood glucose does not easily overlap with that of insulin, resulting in a delay in the peak of blood glucose after the meal, and the risk caused by this delay to patients is that they are prone to pre-meal hypoglycemia. That is, blood glucose has already started to fall, insulin secretion lags behind, and pre-meal hypoglycemia occurs. In addition, the food that the patient eats can also affect the post-prandial blood glucose peak. If the food eaten is high glycemic index, such as watermelon or drinking porridge, the blood sugar rises rapidly and the peak will move forward. If one eats foods with low glycemic index such as mixed grains and coarse grains, the peak will be shifted back or low.