Eating later in the biological day is associated with impaired glucose regulation and reduced insulin sensitivity

Cardiometabolic diseases, including obesity, type 2 diabetes mellitus (T2DM), hypertension, and cardiovascular disease (CVD), remain major global health challenges despite widespread adoption of evidence-based dietary guidelines. Traditional nutrition recommendations have largely focused on dietary composition and energy intake, with limited consideration of the timing of food consumption. Growing evidence indicates that metabolic processes are strongly regulated by circadian rhythms, suggesting that when food is consumed may be a critical but underappreciated determinant of cardiometabolic health. Chrononutrition, which examines the interaction between meal timing and the circadian system, has therefore emerged as an important area of research. This narrative review synthesizes human evidence linking chrononutrition to cardiometabolic outcomes, with a focus on obesity, insulin resistance and T2DM, lipid metabolism, and cardiovascular risk. Findings from observational studies, randomized clinical trials, and mechanistic investigations consistently demonstrate that eating later in the biological day or night is associated with impaired postprandial glucose regulation, reduced insulin sensitivity, altered lipid handling, and adverse cardiometabolic profiles, independent of dietary composition and total energy intake. In contrast, eating patterns aligned with endogenous circadian rhythms characterized by earlier energy intake and avoidance of late-night eating appear metabolically favorable. This review further situates chrononutrition within the framework of precision nutrition. While precision nutrition aims to explain interindividual variability in metabolic responses using genetic, metabolic, and microbiome-based approaches, circadian timing is rarely considered. Because metabolic capacity varies across the day–night cycle, failure to account for meal timing, chronotype, and circadian alignment may contribute to unexplained variability in dietary responses. Integrating chrononutrition into precision nutrition frameworks may therefore improve interpretation of metabolic phenotypes and enhance the personalization of dietary strategies. Finally, key research gaps are identified, highlighting the need for long-term, diverse human studies and time-resolved metabolic phenotyping to clarify the role of chrononutrition in cardiometabolic disease prevention.