Inclusion Criteria:

• Diagnosed with type 2 diabetes mellitus with HbA1c level of 6.0 to 9.0%. Participants with HbA1c of 6.0 to 6.4% were required to be receiving oral glucose lowering medication.
• Diagnosed with type 2 diabetes mellitus for less than 6 years.
• Body mass index of 23 kg/m2 or greater.

Exclusion Criteria:

• Receiving more than two oral glucose-lowering medications.
• Receiving insulin therapy.
• Use of a glucagon-like peptide-1 receptor agonist (GLP-1 RA) within 3 months before study enrollment.
• Use of medications known to affect HbA1c within 3 months before study enrollment, including corticosteroids, vitamin C (excluding vitamin C obtained from natural dietary sources or fruits), vitamin E, trimethoprim-sulfamethoxazole, or hydroxyurea.
• History of diabetic ketoacidosis or hyperglycemic hyperosmolar state within the previous 6 months.
• Unstable psychiatric disorders within the previous 2 years, including major depressive disorder, bipolar disorder, or schizophrenia.
• Pregnant or breastfeeding women, or women planning to become pregnant within 12 months.
• Presence of any of the following medical conditions based on medical history and clinical records, including chronic kidney disease with an estimated glomerular filtration rate less than 45 mL/min/1.73 m2, liver cirrhosis or hepatitis with alanine aminotransferase or aspartate aminotransferase more than 3 times the upper limit of normal, chronic alcohol abuse, hypothyroidism with thyroid-stimulating hormone more than 10 uIU/mL, HIV infection, anemia (hemoglobin less than 10 g/dL), iron deficiency, vitamin B12 deficiency, folate deficiency, thalassemia, glucose-6-phosphate dehydrogenase deficiency, hemolytic anemia, or hemoglobin more than 16 g/dL, heart failure or ischemic heart disease within the previous 6 months.
• History of blood donation or blood transfusion within the previous 3 months.
• Uncontrolled diabetic retinopathy or other uncontrolled retinal disease, including maculopathy, based on medical records.
• Signs, symptoms, or a history of malignancy within 5 years before screening, except for basal cell carcinoma, squamous cell carcinoma of the skin, or other carcinoma in situ.
• Major surgery within 90 days before enrollment or planned major surgery within 6 months after enrollment.
• No access to a smartphone capable of supporting the study application and internet-based data transmission.
• Unable to maintain communication with the study investigators according to the study protocol.