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NCT Number: NCT06936657

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).

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Key information

Conditions

Type 2 Diabetes Mellitus (T2DM) Diabetes Mellitus Diabetes Mellitus, Type 2 Endocrine System Diseases Glucose Metabolism Disorders Metabolic Diseases Nutritional and Metabolic Diseases

Age range

35 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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
  • Signed the informed consent form

Exclusion criteria

  • 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)
  • 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
  • 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
  • Recent use of antibiotics, probiotics, or prebiotics within the past 3 weeks or need for long-term use
  • Unstable medication regimen or use of prescription medications affecting metabolism (e.g., thyroid hormones, glucocorticoids)
  • Pregnancy, breastfeeding, or planning pregnancy
  • Presence of a pacemaker or metal implants, claustrophobia, or other contraindications to fMRI
  • Psychiatric disorders impairing cooperation
  • Expected poor compliance
  • Current or recent (within 4 weeks prior to study initiation) participation in other clinical trials

Treatment and study plan

optimized carbohydrate diet

Other

In this dietary pattern, 50-60% of total energy is derived from carbohydrates, 15-20% from protein, and 25-30% from fat. Among the carbohydrates, resistant starch (RS) constitutes 15-20% of daily starch intake (around 40 g/day), slowly digestible starch (SDS) 5%, rapidly digestible starch (RDS) 75-80%, with dietary fiber at 20-40g per 1000 kcal and free sugars contributing less than 5% of total energy.

conventional diabetes diet

Other

In this dietary pattern, 50-60% of total energy is derived from carbohydrates, 15-20% from protein, and 25-30% from fat. Among the carbohydrates, resistant starch (RS) constitutes 5% of daily starch intake, slowly digestible starch (SDS) 5%, rapidly digestible starch (RDS) 90%, with dietary fiber at 14g per 1000 kcal and free sugars contributing less than 5% of total energy.

Primary outcomes

  1. Change in the average incremental area under the curve (iAUC) of postprandial blood glucose over 3 hours

    Time frame: -2, 0, 10, 16, 18 and 28 weeks

    Average incremental area under the curve (iAUC) of postprandial blood glucose over 3 hours will be measured at -2, 0, 10, 16, 18, and 28 weeks using the continuous glucose monitoring system.

Secondary outcomes

  1. Change in other parameters of Continuous Glucose Monitoring

    Time frame: -2, 0, 10, 16, 18 and 28 weeks

    Other parameters of Continuous Glucose Monitoring, including Time in Range (TIR), Time Above Range (TAR), Time Below Range (TBR), Mean Glucose, Glucose Variability, Glycemic Excursions, Area Under the Curve (AUC), and other relevant metrics, will be assessed at -2, 0, 10, 16, 18, and 28 weeks.

  2. Change in HbA1c

    Time frame: Baseline, 12, 18 and 30 weeks

    HbA1c will be measured at baseline, 12, 18 and 30 weeks. HbA1c will be expressed in mmol/mol.

  3. Change in insulin sensitivity

    Time frame: Baseline, 12, 18 and 30 weeks

    Insulin sensitivity will be assessed at baseline, 12, 18 and 30 weeks.

  4. Change in other clinical biochemical indicators

    Time frame: Baseline, 4, 8, 12, 18, 22, 26 and 30 weeks

    Other clinical biochemical indicators will be measured at baseline, 4, 8, 12, 18, 22, 26 and 30 weeks.

  5. Change in blood glucose

    Time frame: Baseline, 4, 8, 12, 18, 22, 26 and 30 weeks

    Fasting blood glucose will be measured at baseline, 4, 8, 12, 18, 22, 26 and 30 weeks. During meal tolerance test (MTT) at baseline, 12, 18 and 30 weeks, blood glucose at 0, 30, 60, 90, 120 minutes will be measured. Glucose concentration will be expressed in mmol/L

  6. Change in insulin and C peptide secretion

    Time frame: Baseline, 4, 8, 12, 18, 22, 26 and 30 weeks

    Fasting insulin and C peptide concentration will be assessed at baseline, 4, 8, 12, 18, 22, 26 and 30 weeks. During meal tolerance test (MTT) at baseline, 12, 18 and 30 weeks, insulin and C peptide concentration at 0, 30, 60, 90, 120 minutes will be measured. Insulin concentration will be expressed in uU/ml. C peptide concentration will be expressed in ng/ml.

  7. Change in anthropometry and body composition parameters

    Time frame: Baseline, 4, 8, 12, 18, 22, 26 and 30 weeks

    Anthropometry and body composition parameters will be measured at baseline, 4, 8, 12, 18, 22, 26 and 30 weeks.

  8. Change in cognitive function and behavioral performance

    Time frame: Baseline, 12, 18 and 30 weeks

    Cognitive function changes will be assessed using questionnaires (including the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA, Beijing version), Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Trail Making Test, Stroop Color and Word Test, and others) at baseline, 12 18, and 30 weeks. Behavioral performance will be assessed using N-back and other paradigms at baseline, 12, 18, and 30 weeks.

    In addition, subgroups within the two arms will undergo fMRI to assess cognitive function at baseline, 12 18, and 30 weeks.

  9. Change in appetite

    Time frame: Baseline, 12, 18 and 30 weeks

    Appetite will be measured by visual analog scales (VAS) and other relevant scales, and will be assessed at baseline, 12, 18, and 30 weeks.

  10. Change in emotion

    Time frame: Baseline, 12, 18 and 30 weeks

    Emotion will be measured using the PHQ-9 depression screening scale, the Problem Areas in Diabetes (PAID) questionnaire, and other relevant scales at baseline, 12, 18, and 30 weeks.

  11. Change in sleep quality

    Time frame: Baseline, 12, 18 and 30 weeks

    Sleep quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI) questionnaire and other methods at baseline, 12, 18, and 30 weeks.

  12. Change in bowel habits

    Time frame: Baseline, 12, 18 and 30 weeks

    Bowel habits will be assessed using the Bristol Stool Form Scale (BSFS; range: 1-7, with higher scores indicating looser stools) and other relevant scales at baseline, 12, 18, and 30 weeks.

  13. Change in cardiopulmonary exercise testing performance

    Time frame: Baseline, 12, 18 and 30 weeks

    Cardiopulmonary exercise testing performance will be conducted at baseline, 12, 18 and 30 weeks.

  14. Change in blood lipid profiles

    Time frame: Baseline, 4, 8, 12, 18, 22, 26 and 30 weeks

    Blood lipid profiles will be measured at baseline, 4, 8, 12, 18, 22, 26 and 30 weeks.

Other outcomes

  1. Change in the iAUC of postprandial blood glucose over 3 hours after each meal

    Time frame: -2, 0, 10, 16, 18 and 28 weeks

    The iAUC of postprandial blood glucose over 3 hours after each meal in patients with type 2 diabetes will be measured at -2, 0, 10, 16, 18, and 28 weeks using the continuous glucose monitoring system.

  2. Change in hepatic fat content

    Time frame: Baseline, 12, 18 and 30 weeks

    Hepatic fat content will be assessed by Fibroscan at baseline, 12, 18 and 30 weeks.

  3. Change in the levels of cytokines

    Time frame: Baseline, 12, 18 and 30 weeks

    The levels of cytokines, including FGF21, adiponectin, A-FABP, LCN2, and others, will be assessed using Enzyme-Linked Immunosorbent Assay (ELISA) and other methods at baseline, 12, 18, and 30 weeks.

  4. Change in immunologic function

    Time frame: Baseline, 12, 18 and 30 weeks

    The immunologic function will be assessed through isolation and analysis of peripheral blood mononuclear cells at baseline, 12, 18, and 30 weeks.

  5. Change in appetite-related hormones

    Time frame: Baseline, 12, 18 and 30 weeks

    Concentration of appetite-related hormones (e.g., ghrelin, PYY, GLP-1 and others) will be measured at baseline, 12, 18, and 30 weeks.

  6. Change in multi-omics

    Time frame: Baseline, 4, 8, 12, 18, 22, 26 and 30 weeks

    Multi-omics research, including metagenomic sequencing, metabolomics analysis, proteomics, lipidomics, genomics, etc., will be assessed at baseline, 4, 8, 12, 18, 22, 26 and 30 weeks.

Sponsors and collaborators

Lead sponsor

Shanghai 6th People's Hospital

Other

Registry information

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Apr 20, 2025
Registry last updated
Sep 12, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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