New research is sharpening a long-running public health question: how much early childhood diet shapes later development. That focus narrowed this summer with a peer-reviewed study from Children’s Hospital Los Angeles and partner institutions examining whether ultra-processed foods eaten in infancy and toddlerhood were linked to measurable differences years later. The paper adds to a growing body of evidence that food patterns established before kindergarten may still be visible in children’s brains and behavior by school age.
A new study ties early ultra-processed food intake to later brain differences
The specific study at the center of the latest attention is “Early-Life Cumulative Intake of Ultra-Processed Foods and Subcortical Brain Volume at Age Six Years,” published online June 2, 2026, ahead of its August 2026 appearance in The American Journal of Clinical Nutrition, according to PubMed. Researchers followed a prospective birth cohort and evaluated whether cumulative ultra-processed food intake from 6 months through early childhood was associated with cognition and brain structure at later checkpoints.
According to the abstract indexed by PubMed, the study included 144 children for the 24-month cognitive analysis, 93 children for the 72-month cognitive analysis and 79 children for MRI-based brain-volume analysis at age 6. The researchers reported that cumulative ultra-processed food intake was not associated with cognitive performance at either 24 months or 72 months in this cohort. They did, however, find inverse associations between higher intake and volumes in several subcortical brain regions, including the bilateral accumbens, left amygdala, bilateral pallidum, left putamen and bilateral thalamus.
PubMed’s abstract states that, on average, a 10% higher proportion of cumulative ultra-processed food intake was associated with a 1.92% lower subcortical volume. The authors wrote that greater intake from infancy through early childhood was associated with differences in neurodevelopment at age 6, while also calling for future studies to clarify mechanisms and long-term implications. That distinction matters because the study found a structural association, not proof that a toddler diet directly caused later impairment.
What the findings do and do not say for families in the United States
For U.S. families, the clearest confirmed takeaway is not that a single packaged snack in toddlerhood will harm a child’s brain. What is confirmed is that researchers found an association between higher cumulative intake of ultra-processed foods over time and measurable differences in some brain regions by age 6 in the cohort they studied. What is not yet known is whether the same pattern will appear in all U.S. populations, how long those differences persist, or whether they translate into later clinical problems.
The Children’s Hospital Los Angeles-led cohort described in the study involved Latino/Hispanic mother-infant pairs, based on the paper details indexed by PubMed and related institutional summaries. That means the findings are important, but they are not a full national snapshot of every community, income level or eating pattern in the United States. The study also did not show lower test performance on the cognitive measures used at 24 months and 72 months, a point that narrows what can be concluded right now.
Separate research is adding context. A University of Toronto report published March 11, 2026, summarizing a study in JAMA Network Open, said researchers analyzed dietary data from more than 2,000 children at age 3 and later behavioral assessments at age 5. That team found that each 10% increase in calories from ultra-processed foods was linked to higher scores on measures of anxiety, fearfulness, aggression, hyperactivity and overall behavioral difficulties, according to the university’s summary of the study.
Why researchers are focusing on toddler diets now
Researchers and pediatric nutrition experts have been paying closer attention to toddler diets because the early years are when food preferences and eating routines often become established. An American Academy of Pediatrics-related analysis of U.S. toddler diet quality notes that the 2020–2025 Dietary Guidelines for Americans identified a healthy dietary pattern specifically for toddlers 12 through 23 months old, reflecting the policy view that the second year of life is a distinct and important nutrition period. That framework has made it easier for researchers to measure toddler diet quality in more standardized ways.
The latest brain-volume study also fits within a broader nutrition-and-development literature that is increasingly focused on ultra-processed foods rather than single nutrients alone. The authors, as summarized in PubMed, said future work is needed to identify the relevant biological pathways and determine which nutritional factors matter most. That caution is consistent with the paper’s own results, which showed no association with cognitive test performance in the sample even while detecting differences in MRI-measured structures.
For customers and residents reading this as parents or caregivers, the practical implication is limited but clear: this is another data point suggesting that repeated diet patterns in the toddler years may matter later. It does not amount to a recall, safety alert or new federal rule, and it does not establish that specific products cause developmental harm. What it does show, based on newly published and related 2026 research, is that scientists are increasingly treating early childhood nutrition as a measurable part of long-term brain and behavioral health.