High UPF Consumption Linked to Obesity in Canadian Children

High consumption of ultraprocessed foods (UPFs) is associated with obesity in early childhood, especially among young boys, a Canadian cohort study suggests.

UPFs are defined as accessible, ready-to-consume, and convenient food options. Emulsifiers and additives are used to create these shelf-stable foods, most of which are energy-dense and nutritionally imbalanced (eg, with high levels of added sugars, saturated fats, and sodium).

“Canada ranks among the countries with the highest sales of UPFs, so we anticipated high consumption levels,” study author Kozeta Miliku, MD, PhD, assistant professor of nutritional sciences at the University of Toronto, Toronto, Ontario, and clinical science officer for the university’s CHILD Cohort Study, told Medscape Medical News. “However, it was still surprising to find that nearly half of the total daily calorie intake in three-year-olds came from UPFs.”

Furthermore, she said, “the strength of the association between UPF consumption and obesity at such a young age was striking. Even after adjusting for important confounders, the relationship persisted, emphasizing the potential independent impact of UPFs on early obesity risk, although our findings are observational, so we cannot draw causal conclusions.”

The study was published online on January 31 in JAMA Network Open.

Boys More at Risk

Researchers examined the associations among UPF intake, anthropometric adiposity indicators, and obesity status in 2217 Canadian children (53% boys) participating in the CHILD Cohort Study. Diet was assessed during the 3-year visit (September 2011 to June 2016), and anthropometric measurements were assessed at the 5-year visit (December 2013 to April 2018).

Diet intake was evaluated using a semiquantitative food frequency questionnaire (FFQ) at age 3 years. UPFs were identified using the NOVA classification system, which defines UPF based on the extent and degree of food processing. All food items fall into the following four NOVA groups: Unprocessed and minimally processed foods, processed culinary ingredients, processed foods, and UPF.

Anthropometric adiposity indicators were used to calculate age- and sex-standardized z-scores for body mass index (BMI), waist-to-height ratio, subscapular and triceps skinfold thicknesses, and obesity, which was defined using BMI z-score cutoffs.

Multivariable-adjusted regression analyses were used to examine the associations of UPF with adiposity and obesity development, adjusted for parental, birth, and early childhood factors.

At age 3 years, UPF contributed 45% of participants’ total daily energy intake, and the contribution was higher in boys than in girls (46.0% vs 43.9%). Unprocessed and minimally processed foods contributed 37.5% of the total daily energy intake, whereas processed culinary ingredients contributed 2.4% and processed food contributed 15.1%.

Among all participants, higher UPF intake at age 3 years was associated with higher anthropometric adiposity indicators at age 5 years. These findings were primarily driven by boys.

In boys, every 10% UPF energy increase was associated with higher adiposity indicator z-scores for BMI, waist-to-height ratio, and subscapular and triceps skinfold thickness, as well as higher odds of living with overweight or obesity (odds ratio, 1.19).

No significant associations were observed among girls.

Potential explanations for the differences between boys and girls include differences in metabolism, food preferences, appetite regulation, hormonal responses, and gut microbiota between boys and girls, Miliku said.

The study was limited by its use of the 112-item FFQ, which the researchers noted is “not ideal” for capturing UPF intake, and by the NOVA system, which has limitations on interpretability.

“Clinicians should educate families about the importance of minimizing UPF consumption, especially in early childhood, and promote whole, minimally processed foods,” Miliku advised. They also should encourage parents to read food labels and choose nutrient-dense, and home-prepared meals when possible.

In addition, she said, “by emphasizing diet as a key modifiable risk factor, they can urge policymakers to improve food labeling, regulate UPF marketing targeted at children, [improve] school-meal programs (reducing UPF availability and increasing access to fresh, whole foods), and strengthen public health campaigns promoting healthy eating.”

Put the ‘Good Stuff’ Back on the Plate

Jaclyn Lewis Albin, MD, director of the Culinary Medicine Program at UT Southwestern Medical Center in Dallas, commented on the study for Medscape Medical News. Although an observational study can’t prove that UPF consumption causes obesity, she acknowledged, “it adds to the science base sounding the alarm that high consumption of these foods appears to be a risk factor for obesity, independently of total caloric intake.” Albin was not involved in the study.

“These findings in 5-year-old children should motivate everyone to improve early childhood nutritional quality, since childhood sets up many aspects of dietary patterns and health behaviors across the lifespan,” said Albin, who is also medical director of Food Is Medicine Innovation, at the Center for Innovation and Value at Parkland Health, Dallas.

The “good news,” she said, is that “each 10% increase in UPF consumption was associated with increased obesity risk. This means a 10% decrease by making small changes could likely have a similar impact in a positive direction.”

“We must define the boundaries and dosing for food-as-medicine interventions that help people reverse UPF-predominant dietary patterns and deliver the evidence-based support individuals and families need to shift from a predominantly UPF dietary pattern to a predominantly nutrient-dense, whole-food based one,” she continued.

“Fear-based messaging isn’t very helpful, so I always recommend a focus on what to add to the dietary pattern,” she said. “Get the missing good stuff back onto your plate as a first priority and allow that process to gradually push the UPF to the side.”

The CHILD Cohort Study was funded by the Canadian Institute for Health Research and the Allergy, Genes, and Environment Network of Centres of Excellence. GENOME CANADA provided core funding for the CHILD Cohort Study. Miliku reported receiving grant funding from the Canadian Institute for Health Research. Albin reported having no relevant financial relationships.

Marilynn Larkin, MA, is an award-winning medical writer and editor whose work has appeared in numerous publications, including Medscape Medical News and its sister publication MDedge, The Lancet (where she was a contributing editor), and Reuters Health.