Intervention Effects of Optimized Carbohydrate Diet in Patients With Type 2 Diabetes

Intervention Effects of Optimized Carbohydrate Diet in Patients With Type 2 Diabetes

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).

Inclusion Criteria:

1. Patients diagnosed with type 2 diabetes according to the ADA diagnostic criteria
2. HbA1c ≥ 7% and < 9%
3. Antidiabetic medication has been stable for at least 3 months before recruitment
4. Aged 35-70 years
5. Signed the informed consent form

Exclusion Criteria:

1. Treatment with insulin
2. Treatment with GLP-1 receptor agonists or DPP-4 inhibitors
3. Occurrence of diabetic ketoacidosis, lactic acidosis, hyperosmolar coma, or recurrent severe hypoglycemia within the past year
4. 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)
5. Presence of cardiovascular events (e.g., myocardial infarction, stent placement, unstable angina, heart failure, cardiac dysfunction) or cerebrovascular diseases (e.g., intracerebral hemorrhage, ischemic stroke) within the past 6 months
6. Diagnosis of acute or chronic gastrointestinal diseases (e.g., ulcers), hyperthyroidism or hypothyroidism, uncontrolled hypertension, active malignancy not in remission, or other life-threatening diseases
7. Recent use of antibiotics, probiotics, or prebiotics within the past 3 weeks or need for long-term use
8. Unstable medication regimen or use of prescription medications affecting metabolism (e.g., thyroid hormones, glucocorticoids)
9. Pregnancy, breastfeeding, or planning pregnancy
10. Presence of a pacemaker or metal implants, claustrophobia, or other contraindications to fMRI
11. Psychiatric disorders impairing cooperation
12. Expected poor compliance
13. Current or recent (within 4 weeks prior to study initiation) participation in other clinical trials