Eating a lot and still particularly thin, may be physiological factors, may also be gastrointestinal hyperfunction, hyperthyroidism or metabolic diseases and other causes. 1. Physiological factors: If the daily activity is very large, the actual intake is still unable to meet the body’s energy needs. 2. Gastrointestinal hyperfunction: usually due to recent mental stress, overwork or irregular diet, eating more unclean food, etc., which can easily lead to intestinal dysfunction, resulting in gastrointestinal hyperfunction, resulting in faster intestinal peristalsis and increased bowel movements. 3. Hyperthyroidism: due to the increased secretion of thyroid hormones, resulting in high metabolic state, it will show that eat more, lose weight, but also with increased bowel movements, panic, sweating and other manifestations. 4. Other metabolic diseases: such as diabetes, the disease can cause patients to eat a lot, but the weight loss is obvious, getting thinner and thinner, and can also be accompanied by thirst, drinking, and urination and other symptoms. For long-term eating more especially thin situation should be taken seriously, as soon as possible to the hospital, a clear diagnosis of what causes, under the guidance of the doctor symptomatic treatment.