Consumption of ultra-processed foods when very young may increase obesity risk, Canadian study finds

1 February 2025

Canadian children’s dietary habits warrant public health action, say researchers

(Hamilton, ON) New research from the CHILD Cohort Study (CHILD) and the University of Toronto shows that ultra-processed food consumption among preschool Canadian children is alarmingly high. The study also found the consumption of ultra-processed foods by kids in early childhood to be associated with greater risk of living with obesity or overweight, especially among boys. Published in JAMA Network Open, the findings could inform public health initiatives aimed at preventing obesity and associated health problems.

“It is known that the increasing consumption of ultra-processed foods—convenient, ready-to-eat foods with a long shelf-life and low nutritional value, usually high in sugar, saturated fats and salt (like instant noodles and chips, soda, flavoured yogurts)—is causing a public health crisis worldwide,” comments lead author Zheng Hao Chen, a graduate student in nutritional sciences at the Miliku lab at the University of Toronto.

“And it has already been shown that adults who consume these foods are at higher risk of living with obesity. However, our study is important for suggesting that this risk may begin early, among preschool kids, and especially among males.”

The research used data from 2217 participants in CHILD, a major Canadian pregnancy cohort study that has been following close to 3500 kids from before birth into adolescence, collecting information from them at key developmental stages to track the impact of genetic and environmental factors on their longer-term health.

The researchers looked at the early-life dietary habits of these children, based on questionnaires completed by their caregivers when the children were three years old. They compared this information with physical measurements taken of the same kids at age five, including their height, weight, waist size, and skinfold thickness.

The researchers found that, at age three, on average these children were getting nearly half of their daily energy intake from ultra-processed foods. They also found that by age five, kids who consumed these foods had higher body fat measurements and an almost 20% increased risk of living with overweight or obesity. These associations were particularly high among boys whose diets included ultra-processed foods.

“Canada ranks among the top countries for highest sales of ultra-processed foods,” says lead author Dr. Kozeta Miliku, CHILD’s Clinical Science Officer and an Assistant Professor in Nutritional Sciences at the University of Toronto, “so perhaps it should not be surprising that the children in this study consume so much.”

“However, it is still very concerning, especially given the associations we found between these dietary exposures (high ultra-processed food consumption) and the risk of overweight or obesity development. It is also worrisome because long-term eating habits are often set in early childhood.”

“These findings truly warrant public health attention.” adds Miliku.

“To provide kids with a healthier future, Canada must promote healthier food choices in early childhood—through such things as front-of-package-labelling, caregiver nutrition education, dietary recommendations of healthcare professionals, and nutritious menu design in daycare, preschool or school food programs that follow Canada’s Food Guide.”

About Dr. Kozeta Miliku: Dr. Kozeta Miliku is an MD, PhD, Assistant Professor of Nutritional Sciences at the University of Toronto, and Department of Medicine at McMaster University. She is also the Clinical Science Officer of the CHILD Cohort Study and the EDII co-chair of the Canadian Developmental Origins of Health and Disease Society.

About the CHILD Cohort Study: Launched in 2008 by CIHR and AllerGen (a Networks of Centres of Excellence from 2004 to 2019), the CHILD Cohort Study (CHILD) is tracking nearly 3,500 Canadian infants and their families to determine the root causes of chronic diseases such as asthma, allergies and obesity. CHILD has study sites in four provinces and involves over 140 multidisciplinary researchers, students and research staff. Its national headquarters are hosted by McMaster University in Hamilton, ON.

About the Department of Nutritional Sciences, University of Toronto: The Department of Nutritional Sciences is one of the few departments of nutrition in North America to be located within a Faculty of Medicine. This, together with its close linkages with University of Toronto’s Dalla Lana School of Public Health, allows the department to fully explore the relationships between nutrition and human health and disease, and to influence clinical practice and public health programs. It also creates unique opportunities for collaboration with the highest concentration of university-affiliated hospitals, clinicians, and health researchers in North America.

For more information or to request an interview with Dr. Miliku, please contact: Kozeta Miliku Kozeta.miliku@utoronto.ca