Impact of a Targeted Nutritional Intervention on Glycaemic Variability and Correlation Between Glycaemic Parameters and Satiety.

• The primary intervention in this study is dietary counseling and education on adopting a low glycaemic index diet with sample menus provided (Behavioral): At Day 14, participants receive dietary counseling from a department dietician focusing on a low glycaemic index diet. The intervention includes: * Education on low glycaemic index food choices * Provision of sample menus demonstrating low glycaemic index meal planning * Guidance on implementing dietary changes to reduce glycaemic variability The intervention aims to modify eating behaviors by teaching participants to select foods that produce smaller, more gradual increases in blood glucose levels, potentially reducing glycaemic excursions and improving satiety. Duration of intervention effect: 10 days (from Day 10 to Day 20) Monitoring: Participants maintain a food diary recording meal times and food types throughout the study period (Day 0 to Day 20). Continuous glucose monitoring is used to assess glycaemic response before (Day 0-10) and after (Day 10-20) the dietary intervention. Note: The placement of two CGM sensors serves as a
• continuous glucose monitoring (CGM) sensors (Device): Description: Placement of continuous glucose monitoring (CGM) sensors on the back of the participant's dominant arm. Two sensors are placed during the study: * First sensor: Placed at Day 0, worn for 10 days (baseline period) * Second sensor: Placed at Day 10 worn for 10 days (post-intervention period) The CGM measures interstitial fluid glucose concentrations in the range of 40 to 500 mg/dL every 5 minutes for 10 days per sensor. Procedure: Sensors are placed according to manufacturer's recommendations. Participants receive general instructions on sensor maintenance and hygiene. Purpose: The sensors cross the skin barrier to continuously monitor glucose levels, providing data on: * Glycaemic variability (rate of change, coefficient of variation) * Time in range (70-140 mg/dL) * Time in hypoglycaemia (<70 mg/dL) * Time in hyperglycaemia (>140 mg/dL) * Average glucose levels * Glycaemic excursions

Primary outcomes

• Change in Rate of Glycaemic Change (ROC) at Pre- and Post-prandial Time Points [Day 0 to day 10 and Day 10 to day 20]: Difference in the rate of change (ROC) in blood glucose levels (mg/dL/min) measured at each pre-prandial and post-prandial time point, comparing the baseline period (Day 0-10) to the post-intervention period (Day 10-20). ROC is calculated from continuous glucose monitoring data collected every 5 minutes. The change will be analyzed using paired statistical tests comparing mean ROC values before and after dietary intervention.

Secondary outcomes

• Change in Glycaemic Variability Parameters [Day 0 to Day 10 and Day 10 to Day 20]: Change in glycemic variability and CGM-derived glucose metrics from baseline to post-intervention
• Change in Satiety Scores [Day 20]: Change in subjective satiety from baseline (before dietary intervention) to post-intervention, assessed using a Visual Analogue Scale (VAS; 0-100 mm) and the Satiety Labeled Intensity Magnitude (SLIM) Scale.
• Correlation Between Glycaemic Parameters and Satiety Scores [Day 20]: Correlation Between Glycaemic Parameters and Satiety Scores

Sex: All, ages: 12 Years to 18 Years

Inclusion Criteria:

* Adolescents who have entered puberty (Tanner S2+ or G2+)
* Aged over 12 and under 18 years
* Obese, defined by an IOTF Body Mass Index (BMI) > 30
* Child's assent and consent from the person(s) exercising parental authority

Exclusion Criteria:

* Type 2 diabetes: HbA1c > 6.5% or fasting plasma glucose > 1.26 g/L
* Type 1 diabetes
* Treatment capable of altering the glycemic profile (e.g., corticosteroids)
* Intercurrent illness capable of significantly impacting eating behavior (e.g., Prader-Willi syndrome) or the postprandial glycemic profile
* Hypothalamic obesity
* Neuropsychomotor developmental disorders, intellectual disability
* History of bariatric surgery
* Pregnant, parturient, or breastfeeding women
* Persons deprived of liberty by a judicial or administrative decision
* Persons undergoing psychiatric care
* Persons admitted to a healthcare or social care facility for purposes other than the research
* Adults subject to a legal protection measure (guardianship, curatorship)
* Persons not affiliated with a social security scheme or beneficiaries of a similar scheme
* Participation in a study affecting appetite or blood glucose levels