A child’s diet at the tender age of two can significantly impact their cognitive development and learning abilities later in life, as recent research suggests.
Researchers discovered that toddlers who consumed a higher amount of ultraprocessed foods at age two demonstrated lower intelligence scores when they reached ages six and seven. This correlation remained even after accounting for a variety of social, economic, and family factors.
The study analyzed data from the Pelotas Birth Cohort, a long-term research project monitoring thousands of children born in southern Brazil from birth throughout childhood and into the future.
For this research, scholars from the University of Illinois and the Federal University of Pelotas gathered comprehensive dietary information when the children were two years old, later evaluating their cognitive abilities as they entered early schooling.
Rather than focusing on individual foods or nutrients, the researchers examined overall dietary habits. By utilizing a statistical method known as principal component analysis, they identified two primary eating patterns among toddlers.
One of these patterns, deemed “healthy,” comprised foods such as beans, fruits, vegetables, baby foods, and natural fruit juices. The alternative pattern, labeled “unhealthy,” included items like snacks, instant noodles, sweet biscuits, candies, soft drinks, sausages, and processed meats, many of which are classified as ultraprocessed.
Children whose diets aligned more closely with the unhealthy pattern at age two exhibited lower IQ scores by the time they reached six to seven.
Crucially, this connection persisted even after considering multiple factors that could affect cognitive development, such as maternal education, socioeconomic background, family structure, breastfeeding duration, early childhood education, and home stimulation.
Although factors like parental IQ were not directly measured in the cohort, professor Thayna Flores, a lead author of the study, indicated that proxies for the home learning environment were employed, including stimulation measures and preschool attendance.
A surprising discovery was that the healthy eating pattern did not correlate with higher IQ scores. Flores suggested this might be due to the prevalence of healthy foods in the sample, which may obscure subtle differences.
“Approximately 92 percent of children regularly consumed four or more foods that characterize the healthy pattern,” she explained.
The most notable effects were observed among children who were biologically vulnerable. The relationship between unhealthy diets and lower IQ was particularly significant for children who showed early deficits in growth measurements such as weight, height, or head circumference—indicating that inadequate nutrition may intensify existing challenges in physical development.
Though the study did not explicitly investigate biological mechanisms, Flores mentioned that existing research highlights several plausible pathways. Diets high in ultraprocessed foods may influence brain development through mechanisms linked to inflammation, oxidative stress, and alterations in the gut-brain axis.
While this research originates in Brazil, the authors believe that the implications may resonate globally, given the widespread presence of ultraprocessed foods across countries.
In Flores’ view, the message is clear: “We must address the increasing consumption of ultraprocessed foods.” She emphasized the importance of timely interventions to mitigate their prevalence, especially during early childhood.
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Reference
Heller, G. T., Flores, T. R., Carpena, M. X., Hallal, P. C., Domingues, M. R., & Bertoldi, A. D. (2026). Dietary patterns at age 2 and cognitive performance at ages 6–7: An analysis of the 2015 Pelotas Birth Cohort (Brazil). British Journal of Nutrition. https://doi.org/10.1017/S000711452610628X
