The study published earlier this week in JAMA, analyzed the diets of 33,795 children and adolescents nationwide from 1999 to 2018, based on National Health and Nutrition Examinations Surveys (NHANES) data.
Researchers defined ultra-processed foods as "industrially produced and contain ingredients that will rarely be included in culinary preparations" and typically contain added sugars, hydrogenated oils, and flavor enhancers.
Acknowledging the sliding nutrition scale of ultra-processed foods, senior and corresponding author Dr. Fang Fang Zhang, nutrition epidemiologist at the Friedman School, said: "Some whole grain breads and dairy foods are ultra-processed, and they're healthier than other ultra-processed foods.
"Processing can keep food fresher longer, allows for food fortification and enrichment, and enhances consumer convenience. But many ultra-processed foods are less healthy, with more sugar and salt, and less fiber, than unprocessed and minimally processed foods, and the increase in their consumption by children and teenagers is concerning."
Researchers saw the largest spike in calories consumed came from ready-to-eat and ready-to-heat dishes (e.g. takeout, frozen, pizza, burgers), which jumped from 2.2% of calories consumed in 1999 to 11.2% in 2018. The second largest spike in calories came from packaged sweet snacks and desserts, the consumption of which grew from 10.6% to 12.9%.
The estimated percentage of calories consumed from sugar-sweetened beverages, however, decreased from 10.8% to 5.3%, a 51% drop.
"This finding shows the benefits of the concerted campaign over the past few years to reduce overall consumption of sugary drinks," said Zhang.
"We need to mobilize the same energy and level of commitment when it comes to other unhealthy ultra-processed foods such as cakes, cookies, doughnuts and brownies."
'...ultra-processed foods are pervasive in children's diets'
When breaking down the data by race, there was a larger increase in the consumption of ultra-processed foods among non-Hispanic Blacks (10.3%) and Mexican Americans (7.6%) compared to non-Hispanic Whites (5.2%).
There were no statistically significant differences in the overall findings by parental education and family income, according to researchers.
"The lack of disparities based on parental education and family income indicates that ultra-processed foods are pervasive in children's diets," said Zhang.
"This finding supports the need for researchers to track trends in food consumption more fully, taking into account consumption of ultra-processed foods."
Calories from often healthier unprocessed or minimally-processed foods decreased from 28.8% to 23.5%.
The remaining percentage of calories came from moderately processed foods such as cheese and canned fruits and vegetables, and consumer-added flavor-enhancing ingredients such as sugar, honey, maple syrup, and butter.
Ultra-processed foods consumption linked to weight gain
These trends in ultra-processed food consumption are significant, noted researchers, as childhood is a critical period for biological development and the establishment of healthy eating habits, and a diet high in ultra-processed foods is linked to obesity and other chronic health conditions.
"Recent systematic reviews and meta-analyses have found that higher intake of ultra-processed foods is associated with a
range of adverse health outcomes in adults and with overweight or obesity in children."
The study cited previous research on the impact of ultra-processed foods, which found that participants on a diet high in ultra-processed foods consumed more calories and gained more weight in a two-week period, compared with individuals on a whole foods–based diet, despite matching the foods by calories, energy density, macronutrient composition, sugar, sodium, and fiber.
However, more work is still needed to analyze and document the association between ultra-processed food consumption and adverse health outcomes, noted researchers.
"Better dietary assessment methods are needed to document trends and understand the unique role of ultra-processed foods to inform future
evidence-based policy and dietary recommendations. Furthermore, the field will benefit from additional research to clearly define the specific aspects of the rapidly changing global food supply that merit focused attention by consumers, clinicians, and policymakers."
Interested in early childhood nutrition trends and how the food industry is responding to make better-for-you options for kids? Then check out our FOOD FOR KIDS interactive broadcast series on November 7 +10, 2021, and register your interest to stay up-to-date with the latest announcements.