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 for a blood test)

The second type: the digestive tract function is not good. If the digestive organs such as the small intestine and stomach can't work normally, food can't be completely converted into nutrients needed by the body, resulting in low blood sugar concentration, and it is easy to get hungry just after eating. Go for a gastrointestinal examination, even including the mouth, esophagus and gallbladder.

The third type: it may also be caused by too much thyroid hormone secretion, and it will be very thin and grumpy (commonly known as hyperthyroidism, it is recommended to go to the hospital for thyroid test).