If you are hungry, the most direct reason is the decrease of blood sugar concentration, but there may be many reasons. The first type: blood problems. Some people's blood sugar concentration is always lower than the normal concentration due to characteristic (genetic) reasons. As a result, they will stay hungry until they are full. People are weak, their immunity is not strong, and they may often get sick and have no strength. (Go to blood test) The second type: the digestive tract function is abnormal, the digestive organs such as the small intestine and stomach can't work normally, and food can't be completely converted into nutrients needed by the body, which leads to low blood sugar concentration and easy hunger. Soon after eating, (Go to the gastrointestinal examination, even including the mouth, esophagus and gallbladder. The third type: it may also be caused by the secretion of thyroid hormones, which will be very thin and grumpy (commonly known as hyperthyroidism, it is recommended to go to the hospital for thyroid test). Fourth, you can't stand being hungry. It's "worry and hunger" Maybe your liver function is abnormal. When the blood sugar concentration decreases, your liver can't make a correct physiological response to decompose glycogen to maintain normal activity energy, so you continue to consume a small amount of glycogen in the blood, causing more and more serious physiological reactions.