This study will test whether glucose sensor data can be used to identify the time of day when adults with prediabetes are most likely to have high blood sugar after meals. Participants will first wear a continuous glucose monitor and wrist activity monitor and record meal times for 10 days. These data will be used to classify each participant's personal "glycemic vulnerability window," such as morning, evening, or generally variable patterns.
Participants will then be randomly assigned to either personalized meal timing plus a short walk after their most vulnerable meal, or to an attention-matched control group receiving sleep hygiene and general step-count advice. The main outcome will be the change in post-meal glucose exposure during each participant's vulnerable window after 4 weeks.
Age 30 to 70 years
HbA1c 5.7% to 6.4% within 3 months of screening, or
Fasting plasma glucose 100 to 125 mg/dL on two separate occasions
Body mass index 23 to 40 kg/m²
Current or prior diagnosis of type 1 diabetes or type 2 diabetes
Use of glucose-lowering medication within the past 3 months
Use of systemic corticosteroid medication within the past 3 months
Use of prescription weight-loss medication within the past 3 months