Ultraprocessed Foods & Childhood Behavior: Canadian Study Links Diet to Symptoms

A growing body of research is examining the link between diet and child development and a novel study adds to this conversation. Published in JAMA Network Open, research suggests that diets high in ultra-processed foods during preschool years may be associated with slightly increased behavioral symptom scores in young children. Whereas the effects observed were modest, the findings underscore the potential influence of early dietary patterns on emotional and behavioral well-being.

Early Dietary Patterns and Behavioral Development

The study, conducted by researchers in Canada, analyzed data from over 2,000 children, tracking their dietary intake at age three and behavioral outcomes at age five. Researchers found that children who consumed a higher proportion of ultra-processed foods – those that undergo significant industrial processing and often contain high levels of sugar, fat, and salt – exhibited slightly higher scores on measures of behavioral and emotional difficulties. Conversely, the research indicated that modest shifts toward minimally processed foods could be linked to improved behavioral outcomes.

It’s important to understand what constitutes an ultra-processed food. These are formulations made mostly or entirely from substances derived from foods, additives, and cosmetic ingredients, and are typically high in calories, sugar, unhealthy fats, and sodium. Examples include sugary drinks, packaged snacks, processed meats, and ready-to-eat meals. Minimally processed foods, are foods that have been lightly altered for preservation or convenience, such as frozen vegetables or canned beans.

Study Details and Methodology

The research drew upon data from the CHILD Cohort Study, a large, ongoing prospective study following the development of children across Canada. The study assessed dietary intake using food frequency questionnaires completed by parents, categorizing foods according to the NOVA classification system, a widely used method for defining the degree of food processing. Behavioral outcomes were evaluated using the Child Behavior Checklist (CBCL), a standardized questionnaire completed by caregivers that assesses a range of behavioral and emotional symptoms.

Researchers carefully accounted for a number of factors that could influence the results, including maternal education, household income, breastfeeding duration, and the child’s overall calorie intake. They also conducted analyses to explore whether replacing ultra-processed foods with minimally processed foods would have a different effect on behavioral outcomes. The analysis period took place between February and July 2025, using data collected between September 2011 and April 2018.

What the Findings Imply

The study found that for every 10% increase in calorie intake from ultra-processed foods, there was a small increase in behavioral symptom scores. While these increases were not substantial, they were statistically significant, suggesting a potential link between ultra-processed food consumption and behavioral challenges. Importantly, when researchers modeled the effect of substituting 10% of ultra-processed food calories with minimally processed foods, they observed a modest decrease in behavioral symptom scores. This suggests that even small dietary changes could have a positive impact on child behavior.

It’s crucial to emphasize that this study does not prove a cause-and-effect relationship. Correlation does not equal causation. It’s possible that other factors, not measured in the study, could be contributing to both ultra-processed food consumption and behavioral problems. For example, families facing socioeconomic challenges may have limited access to healthy, affordable food options and may also experience higher levels of stress, which could impact both diet and child behavior. The researchers also noted that children included in the final analyses were more likely to have mothers with higher education and household income, which could limit the generalizability of the findings to all populations.

Nuances in the Data

The study also explored specific types of ultra-processed foods and their association with behavioral symptoms. They found that higher intake of artificially sweetened and sugar-sweetened beverages, breads, and ready-to-eat foods was particularly associated with increased internalizing symptoms, such as anxiety, and withdrawal. However, the researchers did not find evidence that the associations differed between boys and girls.

Further analysis revealed that the observed associations remained consistent even after accounting for potential confounding factors such as nutrient intake, changes in dietary patterns over time, and screen time. This strengthens the evidence suggesting a potential link between ultra-processed food consumption and behavioral outcomes, but does not eliminate the possibility of other contributing factors.

Public Health Implications and Future Directions

These findings reinforce the importance of promoting healthy dietary patterns in early childhood. Health Canada’s Canada’s Food Guide emphasizes the consumption of whole, minimally processed foods and limits the intake of ultra-processed foods. Canada’s Food Guide provides recommendations for healthy eating across the lifespan, including specific guidance for infants and young children.

Strengthening efforts to support families in making healthy food choices, such as providing nutrition education, increasing access to affordable healthy foods, and limiting the marketing of ultra-processed foods to children, may contribute to improved behavioral and emotional well-being. Future research should focus on clarifying the long-term effects of ultra-processed food consumption on mental health and exploring the underlying mechanisms that may explain the observed associations. More precise dietary assessments, such as dietary recalls or biomarkers of food intake, could also help to refine our understanding of the relationship between diet and child development. The University of Toronto, which highlighted this research, suggests further investigation is needed to understand the complex interplay between diet, brain development, and behavior.

Ongoing surveillance of dietary patterns and behavioral outcomes in children will be crucial for monitoring trends and informing public health interventions. As our understanding of the link between diet and mental health evolves, it will be important to continue to refine dietary recommendations and develop strategies to support healthy eating habits from an early age.