The child eats normally but is very thin, may be due to physiological or pathological factors, physiological factors such as their own physique; pathological factors such as hyperthyroidism, type 2 diabetes mellitus and so on. 1. Physiological factors: some children due to personal physical reasons, there will be children eat normally but thin, this physical children do not have abnormal performance, its growth and development is not affected, belongs to the physical shape of the thin. 2. Pathological factors: children with hyperthyroidism, due to the increase in thyroid hormones, metabolism increases, the amount of food and drink will be increased than before, but the body is thin; children with type 2 diabetes will also appear to drink a lot of food and drink, but the body is thin; in addition, some consumptive diseases, such as tumors, will make the child appear to eat a normal diet, but the body is thin. Children eat normally but very thin, there may also be other reasons, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.