Consumption of ultra-processed foods is associated with weight gain and decreased well-being in adolescents

A new study examines the impact of ultra-processed foods, screen time and maternal education on adolescent weight and well-being.

In a recent study published in Nutrients, a team of scientists compared ultra-processed food (UPF) intake, sedentary behavior, and well-being among adolescent boys and girls, and examined their association with the risk of being overweight.

Childhood obesity is a growing public health problem linked to dietary habits and sedentary lifestyles, particularly the increasing consumption of ultra-processed foods among adolescents. UPFs are rich in added sugars, unhealthy fats, and additives but poor in essential nutrients, contributing to excess calorie intake and adverse metabolic outcomes.

Sedentary behaviour exacerbates this problem and is particularly common in Western countries and Southern Europe.

Accurate assessment tools are needed to examine UPF consumption and its impact on obesity and well-being in young people, including potential links to mental health. More research is needed to understand these relationships and develop effective interventions.

A total of 245 adolescents (131 boys and 114 girls) aged 12 to 17 years (mean age 14.20 ± 1.09 years) participated in the study, recruited from two randomly selected public schools in the districts of Coimbra (n = 101) and Viseu (n = 144).

Anthropometric data including height, weight and percentage body fat using bioimpedance were collected to calculate body mass index (BMI), which was classified according to the International Obesity Task Force recommendations.

UPF intake was assessed using the NOVA-UPF screening questionnaire, which assesses UPF intake over the previous day. Sedentary behavior was assessed through self-reports, including time spent watching TV and using electronic devices on weekdays and weekends.

Well-being was measured using the Mental Health Continuum Short Form and the Physical Well-Being subscale of the KIDSCREEN-27 questionnaire. Parental education level was used as an indicator of socioeconomic status.

Statistical analysis included descriptive statistics, t-tests, correlations, and logistic regression, adjusting for factors such as age, gender, sedentary behavior, parental BMI, and education. The study complied with the Declaration of Helsinki, was approved by the ethical committees, and participants and their guardians provided informed consent.

In a study involving 245 Portuguese adolescents aged 12 to 17 years (mean age 14.2 ± 1.09 years), the researchers examined UPF consumption, sedentary behavior and well-being, focusing on differences between genders. The sample included 131 boys and 114 girls.

Among girls, 17.5% were overweight and 7.9% were obese; among boys, 15.3% were overweight and 3.1% were obese.

Results showed that adolescents consumed similar levels of UPF across the three NOVA screening food categories, regardless of whether consumption occurred within the past 24 hours or away from home.

On weekdays, the most common sedentary activities were using smartphones, studying, and working on a computer. On weekends, teens spent more time using smartphones, computers, and watching TV.

There were no significant differences in UPF consumption across categories between boys and girls. However, girls had higher levels of BMI and body fat percentage, and both differences were statistically significant (p < 0.001).

Boys used computers more on weekends (p = 0.025) and played electronic games more often on both weekdays (p = 0.005) and weekends (p < 0.001) compared to girls.

Girls, on the other hand, spent more time studying on weekdays (p = 0.006) and on weekends (p = 0.007), and were also more likely to play board games or read on weekends (p = 0.026). In addition, boys showed higher results on all aspects of well-being (p < 0.001) compared to girls.

Correlation analysis showed that UPF consumption in the past 24 hours, including sugary drinks and yoghurts, was positively associated with watching TV on weekends, playing electronic games and using smartphones on weekdays. It was negatively associated with body fat percentage and time spent studying on weekdays and weekends.

A similar trend was observed for UPF consumption outside the home, which was positively associated with total sedentary time on weekends and negatively associated with body fat percentage and study time on weekends.

Consumption of sweet and salty snacks outside the home was negatively associated with body fat percentage. Importantly, no significant associations were found between UPF consumption and aspects of well-being.

Logistic regression controlling for variables such as age, sedentary behavior, gender, parental BMI, and education showed that UPF consumption tended to increase the risk of overweight, but this association was borderline significant (p = 0.06–0.09).

Adolescents whose mothers had a higher level of education were less likely to be overweight or obese (odds ratio = 0.83, 95% CI: 0.70–0.98, p = 0.02). Increased computer use on weekends was associated with a higher likelihood of being overweight (odds ratio = 0.99, 95% CI: 0.98–1.00, p = 0.04).

Ultimately, the study found no gender differences in UPF consumption, which is consistent with international data. Although UPF consumption was associated with an increased risk of being overweight, it was significantly correlated with sedentary behaviors such as screen time.

Adolescents whose mothers had a higher level of education were less likely to be overweight or obese. No significant associations were found between UPF consumption and aspects of well-being.

These findings highlight the complex interaction of dietary habits, sedentary lifestyle and socioeconomic factors in the problem of obesity among adolescents.