Sleepiness after eating is a normal physiological phenomenon in most cases. This is because blood redistribution after eating, and the relative increase of blood supply in the gastrointestinal tract and other places of digestion and absorption will cause relative ischemia and hypoxia in brain tissue, so many people will have the phenomenon of sleepiness after eating. Diabetic patients with elevated postprandial blood glucose may also experience sleepiness after eating. This is because elevated postprandial blood glucose and increased blood viscosity may also lead to tissue ischemia and hypoxia. If blood glucose rises after eating, it will stimulate insulin secretion, and the joint action of insulin and blood glucose will cause the transfer of blood potassium to the cells, resulting in low blood potassium, which will also lead to drowsiness. There is a very easy and effective way to determine if sleepiness after eating is high blood sugar, which is to measure the blood sugar level when you are sleepy after a meal, which helps to determine.