Genetic factors: Some family members are thin and belong to the weak constitution type, which is easy to suffer from chronic diseases.

Disease effects: such as hyperthyroidism, gastrointestinal diseases, diarrhea, peptic ulcer, tuberculosis, tumor, anemia, parasitic diseases, etc.

Poor absorption function.

Mental factors: due to emotional factors, mental anxiety, irregular life, overwork, lack of sleep, physical consumption is more than intake.

Diet: lack of nutrition, insufficient calorie intake or loss of appetite. All diseases can be improved by scientific nutrition, but they need treatment.

I hope I can help you and wish you good health.