This study is a multi-center, randomized, crossover investigator-initiated trial conducted at Shanghai Sixth People's Hospital and other centers. Each participant will undergo two 12-week dietary intervention phases, separated by a 6-week washout, for a total study duration of 30 weeks. Participants will be randomly assigned in a 1:1 ratio to one of two intervention order: (1) optimized carbohydrate diet-washout-conventional diabetes diet, or (2) conventional diabetes diet-washout-optimized carbohydrate diet. The optimized carbohydrate diet is a modified diet with adjusted carbohydrate composition and proportions, while the conventional diabetes diet adheres to an energy-matched protocol in accordance with diabetes dietary guidelines. The study aims to explore the effects of the optimized carbohydrate diet on blood glucose control and glucose metabolism in patients with type 2 diabetes, and to systematically assess its impact on cognitive function and a range of physiological and psychological indicators (such as depression, anxiety, appetite, sleep, bowel habits and others).
Patients diagnosed with type 2 diabetes according to the ADA diagnostic criteria
HbA1c ≥ 7% and < 9%
Antidiabetic medication has been stable for at least 3 months before recruitment
Aged 35-70 years
Treatment with insulin
Treatment with GLP-1 receptor agonists or DPP-4 inhibitors
Occurrence of diabetic ketoacidosis, lactic acidosis, hyperosmolar coma, or recurrent severe hypoglycemia within the past year
Having one or more severe chronic diabetic complications, including advanced diabetic retinopathy, macroalbuminuria (urine albumin-to-creatinine ratio ≥300 mg/g), or impaired renal function (eGFR ≤60 ml/min/1.73 m²)