Fasting blood sugar 4.1mmol/L is not serious. The normal value of fasting blood glucose is 3.9-6.1 mmol/L. Fasting blood glucose 4.1 mmol/L is a normal blood glucose value. Fasting blood glucose ≥7.0 mmol/L, or 2-hour post glycemic load blood glucose ≥11.1 mmol/L, or random blood glucose ≥11.1 mmol/L, accompanied by the symptoms of three more and one less (drinking more, eating more, urinating more, and weight loss) is diagnostic of diabetes mellitus. Fasting blood glucose greater than 6.1 but less than 7.0 mmol/L and 2-hour post glycemic load blood glucose less than 7.8 mmol/L is impaired. Fasting blood glucose of 4.1 mmol/L can be maintained on a daily basis by maintaining the current dietary structure, as well as by appropriate physical activity and by reducing the intake of sugary foods. If the fasting blood glucose is abnormal, it is recommended to consult a doctor in time.