The best time to reverse diabetes is when blood glucose appears mildly high but does not yet meet the diagnostic criteria for diabetes, that is, pre-diabetes. 6.1 mmol/L ≤ fasting blood glucose <7.0 mmo/L and 2 hours postprandial blood glucose <7. 8mmo/L is called impaired fasting blood glucose. Fasting blood glucose <7.0 mmol/L and 7.8 mmol/L <2 hours postprandial blood glucose <11.1 mmol/L are called impaired glucose tolerance. Impaired fasting glucose and impaired glucose tolerance are collectively referred to as prediabetes. In this best reversal period, through reasonable treatment and lifestyle interventions, such as taking medication and insulin treatment, together with controlling diet, insisting on exercise, quitting smoking and limiting alcohol, many overweight or obese type 2 diabetes patients can achieve the effect of "running naked". Of course, even if someone does achieve diabetes reversal in a reasonable way, it is important to maintain a healthy lifestyle, otherwise the disease that was not far away will come back. For patients with a certain duration of diabetes, it is difficult to achieve reversal with reasonable intensive glucose therapy, but it is possible to achieve the goal of reducing medication dosage and complications.