Ultra-Processed Foods Didn’t Drive ADHD Symptoms in This Study, But the Story Isn’t Simple

Researchers have spent years building a circumstantial case that what children eat shapes how their brains behave. Ultra-processed foods, the cookies, sugary drinks, flavored crisps, and pre-packaged noodles that dominate so many children's plates, have emerged as a particular concern given their high levels of added sugars, saturated fats, and sodium alongside near-zero protein and fiber. A new cross-sectional study published in June 2026 by Melda Kangalgil, Zehra Sincar, and Elif Abanoz tested that concern directly in early adolescents, and came back with a more complicated answer than either alarm or reassurance.

Ultra-Processed Food Intake Did Not Predict ADHD Symptom Scores

The study enrolled 101 healthy children between the ages of 11 and 14 in Sivas, Türkiye, between January and March 2025. Parents completed the revised Conners' Parent Rating Scale, a validated tool used to screen for ADHD-related behaviors, while children's diets were assessed using a food frequency questionnaire built on the NOVA classification system, which groups foods by degree of industrial processing rather than nutrient content. Amounts were estimated with a Food Photograph Catalog, and children were included in the reporting process to reduce recall errors.

The median daily ultra-processed food intake across the group was 293.2 g, with a wide spread from 156.1 g at the lower end to 663.7 g at the upper end. When the researchers divided the children into quartiles by UPF consumption and compared ADHD-related scores across those groups, no statistically significant differences emerged (p>0.05). Median scores for cognitive problems and the overall ADHD index were numerically higher in the top quartile, but the gap did not reach statistical significance. The null result held across subgroup comparisons by sex, BMI, chronic disease status, weekday screen time, and physical activity.

Why the Null Result Doesn't Close the Question

A finding of no significant association in a 101-person cross-sectional study is not the same as evidence that no association exists. The sample was deliberately restricted to children without a clinical ADHD diagnosis, which removes the high-symptom end of the spectrum from analysis and shrinks the range of variation the study could detect. The cross-sectional design captures a single snapshot in time, making it impossible to determine whether dietary habits preceded symptom patterns or the other way around. Socioeconomic status and psychosocial stressors, two well-established ADHD risk factors, were not measured or controlled.

Other work points in a different direction. A longitudinal study found that ultra-processed food intake in toddlers aged 3 to 4 was associated with hyperactivity and inattention symptoms in adolescence, suggesting that early exposure during critical windows of brain development may matter more than intake during the early teen years captured here. A large Canadian cohort study similarly linked higher UPF consumption in preschoolers to increased hyperactivity symptoms by age five, with the effect partly reversible when ultra-processed calories were replaced by minimally processed alternatives. A scoping review also concluded that diets high in ultra-processed foods may negatively affect brain development and function during childhood and adolescence, a period when neural circuits are still being shaped.

The authors of the present study acknowledge this tension. They note that an unhealthy dietary pattern high in refined sugars and saturated fats may increase ADHD risk, while a healthier overall diet may offer some protection. That broader diet quality hypothesis is supported by a systematic review and meta-analysis linking higher consumption of sweetened beverages and candies to ADHD symptoms in children and adolescents, though that literature leans on junk food categories rather than NOVA-classified ultra-processed foods specifically.

Screen Time and Sleep Patterns Followed UPF Consumption Quartiles

While the ADHD symptom scores did not separate across UPF quartiles, two behavioral variables did. Children in the highest quartile of ultra-processed food consumption had significantly longer weekend screen time (p=0.045) and significantly longer weekend sleep duration (p=0.039) compared to those in the lowest quartile. No equivalent weekday differences appeared, which the researchers suggest may reflect the confounding influence of school-related screen use on weekdays.

The children in the highest UPF quartile were also significantly younger than those in the lowest quartile (p=0.004), a finding the authors flag as a potential confounder for the screen time association, since younger children may cluster differently on both variables. Age-adjusted analyses were not performed, which limits how much weight can be placed on those secondary correlations.

The broader impact of ultra-processed foods on pediatric health encompasses more than ADHD risk: higher UPF intake in children has been linked to obesity, gut microbiome disruption, increased DNA damage, and allergic disease. In that context, the screen time and sleep associations observed here, even if preliminary, point toward a cluster of behaviors worth tracking together.

What Future Research Needs to Resolve

This study carves out useful negative space. Among healthy early adolescents in a Turkish sample, consuming more ultra-processed food in the 293 g per day range did not translate into measurably higher parent-rated ADHD symptoms. That boundary condition matters for calibrating expectations. But several design limitations keep the picture incomplete.

Longer, prospective studies that follow children from early childhood, include both diagnosed and undiagnosed groups, measure socioeconomic and psychosocial covariates, and use objective dietary tracking over multiple time points would be needed to resolve whether the early-life associations seen elsewhere extend into adolescence. The question of whether the effect is specific to ultra-processed foods as a category or to particular ingredients, added sugars being the most commonly implicated in behavioral research, also remains open. Research on whether ADHD symptoms themselves drive children toward less healthy diets, rather than the reverse, adds another layer of complexity: one prospective study suggested the relationship between ADHD symptoms and diet quality may be largely unidirectional, with ADHD predicting poor diet rather than poor diet predicting ADHD.

For now, the Kangalgil et al. study is a careful null result from a small, restricted sample. It does not exonerate ultra-processed foods in the context of neurodevelopmental health, but it does suggest that the relationship, if real, is not simple enough to show up cleanly in a brief snapshot of early adolescence.

Evidence rating

INVESTIGATIONAL — 61/100

Caveats:

• No statistically significant association was found between ultra-processed food intake and ADHD symptoms — this study's main finding is a null result.
• Cross-sectional design cannot establish cause and effect.
• Small sample of 101 children from a single city in Türkiye limits generalizability.
• Study excluded children with an existing ADHD diagnosis, so findings apply only to subclinical symptom variation in a healthy sample.
• Key confounders including socioeconomic status and psychosocial stressors were not measured or controlled.
• Funding source was not disclosed.

Single-site cross-sectional study of 101 children aged 11–14 in Türkiye. Found no statistically significant association between ultra-processed food consumption and ADHD symptom scores. The design establishes association at best, not causation, and the small, geographically homogeneous sample limits generalizability. Key potential confounders were not measured, and findings have not been independently replicated.

References

1. Melda Kangalgil, Zehra Sincar, Elif Abanoz (2026). THE RELATIONSHIP BETWEEN ULTRA PROCESSED FOOD CONSUMPTION AND ATTENTION DEFICIT HYPERACTIVITY DISORDER SYMPTOMS IN CHILDREN. İnönü Üniversitesi Sağlık Hizmetleri Meslek Yüksek Okulu Dergisi. https://doi.org/10.33715/inonusaglik.1733753
2. Paula Dal Bo Campagnolo, Angela Helena Marin, Marcia Regina Vitolo, Ricardo Campos Ferreira (2024). Early ultra-processed foods consumption and hyperactivity/inattention in adolescence. Revista de Saúde Pública. https://doi.org/10.11606/s1518-8787.2024058005636
3. Association of Ultraprocessed Food Consumption With Internalizing and Externalizing Behaviors in Early Childhood. JAMA Network. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2816075
4. Impact of Ultra-Processed Foods on Brain Development and Function in Children, Adolescents, and During Pregnancy: A Scoping Review. frontiersin.org. https://www.frontiersin.org/articles/10.3389/fpubh.2023.1237468/full
5. Jade L. Kearsey, Elisha West, Nelia Vairinhos, et al. (2023). Evaluation of a Nutrition Education and Skills Training programme in vulnerable adults who are at high risk of food insecurity. Journal of Human Nutrition and Dietetics. https://doi.org/10.1111/jhn.13264
6. The impact of ultra-processed foods on pediatric health – PMC. NIH. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10331613/
7. Diet Quality and Attention-Deficit/Hyperactivity Disorder Symptoms in Children: A Prospective Population-Based Study. academic.oup.com. https://academic.oup.com/jn/article/149/11/1963/5512273