Abstract
The vital role of early dietary intake in shaping later health has been widely acknowledged, but how changes in dietary intake from early life influence health outcomes remains unclear. This review systematically synthesized the literature that examined the longitudinal associations between changes in dietary intake (i.e., trajectories) from early life and health outcomes. Electronic searches were conducted in PubMed, Embase, and ScienceDirect to gather longitudinal cohort studies that investigated dietary intake trajectories from infancy, childhood, or adolescence (with first dietary assessment before age 18 y) and any health outcomes published from inception to September 2024 (CRD42024512716). Of 16 included studies, 14 reported significant associations between dietary intake trajectories (intakes of macronutrients, food groups, diet quality or dietary patterns) in childhood or from childhood to adolescence/early adulthood and dental, obesity, cardiometabolic, neurocognitive, liver or gut health outcomes from age 2 y up to age 41 y. Most studies were of high (n = 2) or acceptable (n = 12) quality. A high or increasing sugar intake trajectory during infancy was linked to an increased risk of dental caries in early childhood, whereas a healthy dietary pattern trajectory was associated with lower risk. Trajectories of poor diet quality, red meat dietary pattern, and high discretionary food intake from infancy/early childhood were associated with adiposity and adverse cardiometabolic outcomes at adolescence and adulthood. Significant associations were also found between trajectories of dietary patterns or macronutrient intakes (e.g., protein, carbohydrate, and dietary fiber) from infancy and neurocognitive outcomes in childhood. High energy intake trajectory from early childhood to adolescence and carbohydrate intake from infancy to early adulthood were associated with poor liver health outcomes and gut microbiota composition in adulthood, respectively. Dietary intake trajectories established from infancy or early childhood were associated with various health outcomes. Dietary interventions should be initiated from infancy or early childhood for early health promotion.