After eating some people often experience dizziness, brain swelling, and often accompanied by sleepiness, thinking about sleep. After a meal, the gastrointestinal tract does a lot of work and blood is concentrated to the gastrointestinal tract, which changes the distribution of blood and reduces the relative supply to the brain, thus causing symptoms of insufficient blood supply to the brain. During meals, the gastrointestinal tract peristalsis, grind the food and then secrete a large amount of digestive juices to break down the food. In the small intestine, food is absorbed and transformed into energy for input to all parts of the body. This process itself consumes a lot of energy, and the main source of energy supply is blood, which is concentrated in the gastrointestinal tract during meals, so that the blood supply to other parts of the body is relatively reduced. The brain is a very sensitive part to ischemia and hypoxia, and it is a normal physiological phenomenon to experience dizziness, brain swelling and sleepiness when ischemia and hypoxia occur.