Instead of eating staple food, high blood sugar may be related to physiological or pathological factors, such as diabetes mellitus and pheochromocytoma. 1. Physiological factors: (1) Strenuous exercise: If you don’t eat staple food, your blood glucose will rise after strenuous exercise, which is mainly related to the increase of blood glucose-raising hormone in the body. Sympathetic nerve excitation after exercise, at the same time, the increase of catecholamine secretion, the increase of norepinephrine secretion, will make the blood sugar rise. 2. Pathologic factors: (1) Diabetes mellitus: the function of patients’ pancreatic islet cells is significantly impaired, as glucose cannot enter the cells normally for metabolism and remains in the blood circulation. Even if no staple food is eaten, it will cause blood sugar to rise. (2) Pheochromocytoma: catecholamine-secreting tumors produced by neural crest-originated pheochromocytes lead to an abnormal increase in the secretion of epinephrine and norepinephrine, which can also lead to elevated blood glucose. When there is high blood sugar instead of eating staple food, it is recommended to consult a doctor in time, follow the doctor’s instructions for further examination, and carry out targeted treatment or therapy with the doctor’s help.