The goal of this clinical trial is to evaluate the intervention effects on blood sugar levels using an AI diet app for personalized meal control and the continuous glucose monitoring system (CGMS) in patients with type 2 diabetes (T2D) The main questions it aims to answer are: 1\. Effect of glycemic control on hemoglobin A1c (HbA1c) in T2D patients through continuous glucose monitoring system (CGMS) 2 Effect of blood sugar management intervention using AI diet app ◎ Research method \<study arms\> * Negative Control group (NC) 20 people (\*24 people) checking only hemoglobin A1c (HbA1c) three times (at the beginning of the study, after the 1st 12 weeks, and then after the 2nd 12weeks) * Positive control group (PC) 30 people (\*36 people) wearing the CGMS patch for 12 weeks and checking HbA1c three times * Intervention group (IG) 30 people (\*36 people) using CGMS patch for diabetes, AI diet app, and checking HbA1c three times (\* Actual number of recruits considering dropout) This study's aim is to identify dietary factors for each patient that can affect blood sugar control based on the Continuous Glucose Monitoring System (CGMS) in patients with T2D and to personalize the amount and type of meal intake. It is planned to confirm the effect of blood sugar control intervention through a nutrition counseling coaching system. The sex-stratified random assignment method was used to recruit 20, 30, and 30 study participants in the control group (negative), control group (positive), and intervention group, respectively. Namely, each study group is allocated according to the endocrinology department visiting patients, so the ratio of participants by gender is similarly allocated. The group allocation of subjects uses a double-blind method in which a researcher who is not at all related to research planning, analysis, and interpretation of results assigns subjects according to random sampling numbers.