1Nupens/usp, São Paulo, Brazil, 2Harvard T.H. Chan School of Public Health, Boston, USA.
Background & aims: few longitudinal studies have been conducted on ultra-processed food (UPF) and weight gain in low- to middle-income countries (LMIC), especially with young adults and with an innovative appropriate instrument to capture UPF consumption. We aim to evaluate the prospective associations between UPF consumption and incidence of 10% or more gain in body mass index (BMI) in Brazilian young adults. Methods: the study population are 18-29 years old Brazilians enrolled at NutriNet-Brasil study, an open web-based cohort for volunteers that started enrollment in January 2020. All variables were self-reported. UPF consumption (percentage of caloric contribution in diet) was assessed by two 24-hour food recalls and categorized into quartiles. The participants had 1-3 measures of weight at follow-up. Multivariable cox regression models were performed to examine the association between the exposure and the incidence of 10% or more gain in BMI. Included covariates were sex, age, housing macro-region, years of schooling, goods and services score, skin color, leisure physical activity, smoking, sleep, leisure screen time, alcohol consumption, lower than usual caloric intake and BMI at baseline. Participants who reported pregnancy at any time point of follow-up or who had implausible measurements of weight, height, age, and caloric intake were excluded. Results: 2,105 young adults were included in the analyses. With a mean follow-up of 17.2 months, there were 234 outcome cases. The higher the UPF consumption, the greater the chance for weight gain in the adjusted models for the total sample and of women (p-trend < 0.05). Using the first quartile of UPF consumption as a reference, in the last quartile the risk of weight gain increased by 65% for the total sample, and in 72% for women. Conclusions: The results confirm the direct relationship between the consumption of ultraprocessed foods and weight gain and reinforce the need to implement and/or strengthen public policies that discourage UPF consumption.
Keywords: longitudinal study, ultra-processed food consumption, 24-hour food recall, weight gain.