Personalized Meal Timing and Walking Based on Glucose Patterns in Adults With Prediabetes

Summary

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.

Eligibility

Inclusion Criteria:

* Age 30 to 70 years
* Prediabetes, defined as either:
* 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
* Owns a smartphone compatible with study applications
* Willing to wear a continuous glucose monitor and wrist activity monitor during the study period
* Willing to record meals using timestamped meal-photo logging
* Able to provide written informed consent

Exclusion Criteria:

* 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
* Current shift work
* Transmeridian travel across more than 2 time zones within 4 weeks before enrollment
* Known untreated or unstable sleep disorder, including obstructive sleep apnea, narcolepsy, or insomnia disorder
* Pregnancy, planned pregnancy, or breastfeeding
* Gastrointestinal disease or surgery likely to affect nutrient absorption
* Current participation in a structured dietary or exercise intervention program
* Estimated glomerular filtration rate less than 60 mL/min/1.73 m²
* Inability or unwillingness to comply with continuous glucose monitoring, wrist actigraphy, meal logging, or study visits

Conditions4

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