Abstract
Gestational diabetes mellitus (GDM) is a heterogeneous disorder that compromises maternal and offspring health. Conventional medical nutrition therapy focuses on nutrient composition and caloric targets but largely omits timing and individualized biology. This narrative review synthesizes mechanistic, epidemiologic and interventional evidence linking circadian biology and meal timing (chrononutrition) to maternal glycemic control. Observational cohorts associate late eating and breakfast skipping with worse glycemia, while pilot interventions and CGM-based studies indicate that front-loading carbohydrates, restricting evening carbohydrate, extending overnight fasting (≈10-12 h), and simple within-meal sequencing can reduce postprandial excursions and increase time-in-range. We propose a pragmatic, tiered clinical pathway in which routine second-trimester triage (50 g glucose challenge test and ultrasound abdominal subcutaneous fat thickness) identifies higher-risk women for short-term CGM phenotyping and prioritized chrononutrition counseling. Integrating phenotype-matched timing interventions with dietetic support and digital decision tools allows rapid, individualized adjustments informed by real-time glucose patterns and patient chronotype. In principle, this tiered strategy could improve daily glycemic profiles, reduce the need for pharmacotherapy, and translate into better neonatal outcomes if supported by larger randomized trials. Chrononutrition therefore offers a promising extension of standard care: simple, low-cost adjustments to "when" food is eaten, supported by digital tools, could allow nutrition therapy for GDM to become more precise, more responsive, and ultimately more effective for both mother and child. Key priorities include validating bedside and chrono-omic stratifiers, testing scalable delivery platforms, and ensuring equitable access to personalized chrononutrition in pregnancy.