The incidence rate of cachexia in malignant tumors is high and about 20% of patients with malignant tumors die of cachexia. Persistent skeletal muscle depletion is a core manifestation of cachexia leading to a serious decline in the quality of life of patients an increase in the incidence of complications and mortality. Clear diagnosis staging and grading are necessary for patients with malignant tumors which is beneficial for their anti-tumor and nutritional treatments. Patients with malignant tumors exhibit low intake and metabolic abnormalities both of which can lead to a negative balance of protein and energy. It is necessary to increase energy and nutrient intake to correct the negative balance of energy and protein. Close nutritional follow-up nutritional counseling and patient nutrition education are important measures for preventing and treating tumor cachexia. Simply choosing different foods and understanding their intake can help patients consume more energy and nutrients which may help improve their nutritional status.