UK teenagers get two-thirds of their daily calories from ultra-processed food, research finds

19 Jul 2024 --- Around two-thirds of UK adolescents’ daily energy intake comprises ultra-processed foods (UPFs), although consumption decreased by 4.8% from 2008 to 2019. The new study finds the highest UPF consumption among adolescents with lower socioeconomic status, white ethnicity and living in Northern England. 

The study uses data from four-day food diaries from 2,991 adolescents (aged 11–18) in the UK National Diet and Nutrition Survey from 2008–09 and 2018–19. The research team estimated the UPF percentage of participants’ total energy intake and absolute weight. 

“Adolescents’ food patterns and practices are influenced by many factors, including their home environment, the marketing they are exposed to and the influence of their friends and peers. But adolescence is also an important time in our lives where behaviors become ingrained,” says Dr. Yanaina Chavez-Ugalde from the Medical Research Council Epidemiology Unit at the University of Cambridge, UK, the study’s first author.

“Our findings clearly show that UPFs make up the majority of adolescents’ diets, and their consumption is at a much higher level than is ideal, given their potential negative health impacts.”

Experts continue to debate the usefulness of using a food’s processing level to determine its healthiness, instead urging food classifications to focus on a food’s nutrient profile. Research indicates that not all UPF categories have the same impact on health risk. 

“Slight fall” in UPF consumption 
The study, published in the European Journal of Nutrition, details that adolescent UPF consumption fell from 68% in 2008–09 to 63% in 2018–19. The researchers note that mean UPF consumption amounted to 861 g daily, accounting for an average of 65.9% of total energy intake. 

According to the authors, this reduction may partly be explained by “increased public awareness and health concerns associated with sugar consumption, government-led campaigns and sugar-sweetened beverages reformulation to reduce sugar content.” 

At the same time, the study finds that UPF contributed proportionally more to total energy intake (65%) than it did to food weight (43%). The authors note that this reflects the higher energy density of UPFs associated with weight gain and diabetes. 

The researchers hope to guide policymakers to design effective policies to combat the negative effects of UPF consumption.Influencing factors 
The authors illustrate that parents’ occupation, ethnic group and UK region influence the proportion of calorie intake from UPFs. For example, adolescents from disadvantaged backgrounds consumed an average of 68.4% of total calorie intake from UPFs, compared to 63.8% in less underprivileged backgrounds. 

Adolescents of non-white ethnicity consumed a lower proportion of daily calorie intake from UPFs (59% compared to 67.3%), and those living in the North of England consumed a higher proportion of calories from UPFs than adolescents living in the South and London (67.4% vs. 64.1%). 

Moreover, UPF consumption was slightly larger among 11-year-olds than 18-year-olds (65.6% compared with 63.4%). 

“Our findings suggest that disparities in consumption of UPFs are not just down to individual choices. We hope this evidence can help guide policymakers in designing more effective policies to combat the negative effects of UPF consumption among youth and the ripple effects this has on public health,” underscores Dr. Zoi Toumpakari from the Centre for Exercise, Nutrition and Health Sciences at the University of Bristol, UK, and joint senior author of the study. 

Regarding weight, the researchers note that higher UPF consumption (g/d) was associated with “being male, white, aged 18, having parents with routine or manual occupation, living in England North and living with obesity.” 

Research limitations 
The authors note several limitations of the study, such as its observational nature, which only allows the researchers to report associations, not causal links. 

Commenting on the study’s findings, Dr. Duane Mellor, dietitian and spokesperson for the British Dietetic Association, also urges that the identified declining UPF consumption be treated cautiously. 

He explains: “The same young people do not report what they have eaten yearly, as different people are asked to complete a food diary every year. So, very different people from similar backgrounds may have very different dietary habits each year, so it is hard to draw conclusions when some years seem different to others — it could be purely down to chance.” 

Experts continue to debate the usefulness of using a food’s processing level to determine its healthiness.“The authors are also very clear that the classification of foods as ultra-processed based on four-day food diaries is open to errors as the method is not designed to be used to estimate UPF intake, and the NOVA classification is not designed to be applied to the UK diet, let alone different variants of the British diet.”

Mellor adds that foods could be misclassified without details on how a product is made. For example, a homemade pie could be reported as a “cheese and onion pie” in a food diary, which, although not a healthy choice, would not meet NOVA’s criteria for a UPF. 

“Safe” UPF levels 
According to the authors, there are no “universally agreed ‘safe’ levels of dietary share from UPFs,” they call for additional research to determine the harm of UPFs on health and improve the nutritional quality of adolescent diets. 

Also commenting on the study’s findings, Dr. Aisling Daly, lecturer in nutrition at Oxford Brookes University, UK, underscores that the research lacks a connection to other health aspects, specific nutrients (such as fat or fiber) and the actual or potential effects of this consumption. 

“UPFs have many plus points, being relatively affordable, tasty, easy to prepare and convenient to fit into an adolescent lifestyle, but there may be a risk of assuming the higher consumption is a negative thing for health.” 

For example, study participants with higher physical activity levels also showed higher UPF consumption, which Daly notes indicates a potential connection between this health-promoting behavior and higher UPF consumption. 

“It would be interesting to see any connections with other nutrients, other markers of health or health behaviors and UPF consumption, to give a rounded picture on these relationships and the potential impacts of UPF consumption.”

She cautions that any research based on the NOVA UPF category “must be interpreted with care” since some UPFs are less harmful to health and serve helpful roles in the diet, such as unsweetened cereals and several dairy products. 

By Jolanda van Hal