60 participants will be recruited from outpatients or inpatients in First Affiliated Hospital of Sun Yat-sen University according the eligibility criteria. All the eligible subjects will be randomly allocated into 2 groups, the fasting group and the intense insulin therapy group. The former one will receive fasting therapy for 14 days and the latter be treated with an intense insulin therapy including short-term continuous subcutaneous insulin infusion treatment or four stage intensive insulin treatment for 2 weeks.