Table 1.

Summary of the selected studies that investigated the association between the UPF consumption and obesity and adiposity parameters in children and adolescents

Authors, year and country	Study design	Study population	Exposure variable and assessment	Outcomes and methods	Confounders	Main results
Louzada et al. (2015), Brazil [21]	Cross-sectional	7534 adolescents aged 10–19 years	%UPFeneergy; quintiles Two 24-h dietary recalls on 2 non-consecutive days	BMI; risk of obesity (BMI-for-age z score ≥  + 2); risk of weight excess (BMI-for-age z score ≥  + 1)	Age, sex, race, region, urban status, smoking, physical activity, education, per capita household income, consumption of fruits, vegetables and beans, interaction between sex and income	Adolescents in the upper quintile of UPF consumption had a BMI (mean difference 0.84 kg/m2, 95% CI − 0.16, 1.85; Ptrend = 0.08) and the risk for excess weight (OR = 1.52, 95% CI 0.75, 3.07; Ptrend = 0.250) similar to adolescents in the first quintile of UPF consumption. A positive significant trend was observed between the UPF consumption and the risk for obesity, but adolescents in the upper quintile had the same risk for obesity of those in the lower quintile (OR = 2.74, 95% CI 0.78, 9.60; Ptrend = 0.05)
Melo et al. (2017), Brazil [22]	Cross-sectional	249 adolescents aged 14–19 years; 45.2% boys and 55.8% girls	Daily frequency of UPF consumption; group 1 (less than weekly) and group 2 (weekly or more) Food frequency questionnaire (84-food items)	Excess of body weight (BMI-for-age z score >  + 1) and high WC identified using sex- and age-specific cutoff values	Age and sex	No association was found between the frequency of consumption of UPF and the excess of body weight (PR = 0.76, 95% CI 0.47, 1.22; P = 0.25) and high WC (PR = 0.94, 95% CI 0.51, 1.72, P = 0.85)
Cunha et al. (2018), Brazil [23]	Longitudinal prospective cohort	1035 adolescents aged 14–20 years; 46% boys and 54% girls	Daily frequency of UPF consumption; quartiles Food frequency questionnaire (FFQ: 72 food items)	BMI at baseline and at 1- and 2-year follow-up; %BF by bioelectric impedance at baseline and at 2-year follow-up	Type of school (public or private), sex, physical activity levels, and underreporting (a dummy variable for energy intake below the 10th percentile)	An inverse association was found between the frequency of UPF consumption and BMI, both at baseline and at 1-year follow-up, and %BF at 2-year follow-up
Costa et al. (2019), Brazil [24]	Longitudinal	315 children aged 4 years; 57% boys and 43% girls	%UPFeneergy; continuous Two 24-h dietary recalls on 2 non-consecutive days at baseline and four years later	BMI, WC, WHtR and skinfolds sum (tricipital and subscapular) changes from 4 to 8 years old	Group status in the early phase (intervention and control), mother’s pre-pregnancy BMI, sex, birth weight, breast-feeding, family income, maternal schooling and total screen	UPF consumption at 4 years old was associated with increased WC change from preschool to school age (β = 0.07, 95% CI 0.01, 0.14; P = 0.030). No association was found between the UPF consumption and BMI (β = 0.00, 95% CI − 0.02, 0.01; P = 0.569), WHtR (β = 0.00, 95% CI 0.00, 0.00; P = 0.108) and skinfolds sum (β = 0.05, 95% CI − 0.04, 0.15; P = 0.282) changes
Viola et al. (2020), Brazil [25]	Cross-sectional	1525 adolescents aged 18–19 years; 47.1% boys and 52.9% girls	%UPFeneergy; continuous Food frequency questionnaire (FFQ: 106 food items)	BMI, WC, %BF by air displacement plethysmography (BODPOD), muscle mass, LMI and android fat by DEXA	Sex, education, socioeconomic status, total daily energy intake, dieting to lose weight, physical activity, consumption of alcoholic beverages, smoking, and sleeping hours	Inverse relationship between the consumption of UPF and BMI (β = − 0.01 kg/m2, 95% CI − 0.03, − 0.01; P = 0.021), muscle mass (β = − 0.04 kg, 95% CI − 0.06, − 0.02; P < 0.001), and LMI (β = − 0.01 kg/m2, 95% CI − 0.02, − 0.01; P < 0.001). No association was found between the consumption of UPF and %BF, WC and kg of android fat
Oliveira et al. (2020), Brazil [26]	Cross-sectional	164 children aged 7–10 years; 40.9% boys and 59.1% girls	%UPFeneergy; continuous Three 24-h recalls carried out on non-consecutive days (one of them on weekend)	BMI, WC and WHtR	Age, sex and total caloric intake	No significant association was found between the UPF consumption and BMI (β = − 0.004, 95% CI − 0.057, 0.048), WC (β = − 0.037, 95% CI − 0.167, 0.092) and WHtR (β = 0.001, 95% CI − 0.001, 0.001)
Bleiweiss-Sande et al. (2020), United States [27]	Cross-sectional	131 children aged 6–12 years from low-income communities; 58% boys and 42% girls	%UPFeneergy; continuous Three 24-h recalls carried out on non-consecutive days (one of them on weekend)	BMI-for-age z score	Sex, days of National School Breakfast and National School Lunch Program participation	No association was found between the UPF consumption and BMI-for-age z score (β = 0.0006; 95% CI − 0.0068, 0.0080; P = 0.87)
Costa et al. (2021), Brazil [28]	Longitudinal prospective cohort	3128 children aged 6 years; 51.8% boys and 48.2% girls	Daily intake of UPF (grams) from 6 to 11 years of age; continuous Food frequency questionnaire (54-food items and 88-food items at 6- and 11-year follow-ups	FMI from 6 to 11 years of age. Body fat was measured by air displacement plethysmography (BODPOD)	Model 1: Maternal age, schooling and skin color, participant sex, birthweight, time spent watching TV, daily energy intake: expenditure ratio Model 2: Model 1 + consumption of foods other than UPF (g/day) Model 3: Model 1 + daily energy intake	UPF consumption was associated with FMI change between 6 and 11 years of age. In model 1, a daily increase of 100 g in the contribution from UPF was associated with a FMI gain of 0.09 kg/m2 (95% CI 0.07, 0.10; P < 0.001). In model 2, a daily increase of 100 g in the contribution from UPF was associated with a FMI gain of 0.14 kg/m2 (95% CI 0.13, 0.15; P < 0.001). In model 3, a daily increase of 100 g in the contribution from UPF was associated with a FMI gain of 0.05 kg/m2 (95% CI 0.04, 0.06; P < 0.001)
Chang et al. (2021), England [29]	Longitudinal prospective cohort	9025 children: 80.5% (n = 7264) aged 7 years, 16.8% (n = 1519) aged 10 years of age, and 7.2% (n  = 242) aged 13 years; 50.3% boys and 49.7% girls	%UPFintake; quintiles 3-day food diary (79.0% of cases), 2-day food diary (13.0% of cases) and 1-day food dairy (8.0% of cases)	Primary outcomes: BMI, FMI, LMI and %BF measured by DEXA from recruitment to 24 years old Secondary outcomes: BMI-for-age z score, weight, WC, fat mass and lean mass by DEXA from recruitment to 24 years old	Child's sex, ethnicity, birth weight, physical activity, quintiles of Index of Multiple Deprivation and total energy intake, and mother's pre-pregnancy BMI, marital status, education and socioeconomic status	Primary outcomes: At baseline, children in the upper quintile of UPF consumption had higher mean values for FMI (+ 0.27 kg/m2, 95% CI 0.09, 0.45) and %BF (+ 1.47%, 95% CI 0.81, 2.13), but not for BMI and LMI, compared to children in the first quintile. Growth trajectories for BMI and FMI were significantly higher in the fifth quintile compared to the first quintile by an additional 0.06 kg/m2 (95% CI 0.04, 0.08) and 0.03 kg/m2 (95% CI 0.01, 0.05) per year, respectively Secondary outcomes: At baseline, children in the upper quintile of UPF consumption had higher mean values for FM (+ 0.51 kg, 95% CI 0.08, 0.93), but not for body weight, WC, BMI-for-age z score and lean mass, compared to children in the first quintile. Growth trajectories for body weight, WC, BMI-for-age z score and FM were significantly higher in the fifth quintile compared to the first quintile by an additional 0.20 kg (95% CI 0.11, 0.28), 0.17 cm (95% CI 0.11, 0.22), 0.01 z score (95% CI 0.003, 0.01) and 0.15 kg (95% CI 0.08, 0.21) per year, respectively
Vedovato et al. (2021), Portugal [30]	Longitudinal prospective cohort	1175 children aged 4 years; 52% boys and 48% girls	Calories from UPF (kcal/day); continuous 2-day or 3-day food dietary records (1 or 2 weekdays and 1 weekend day) at 4 and 7 years of age	BMI-for-age z score at 10 years	Maternal age, education and BMI before pregnancy, exclusive breast-feeding for the first 6 months, parental concern on eating behaviors, child BMI z score, practice of physical exercise and daily screen time at 4 years of age	The UPF consumption at 4 years old was significantly associated with BMI-for-age z score at age 10 (β = 0·028; 95% CI 0·006, 0·051 every 100 kcal/day from UPF). No association was found between the UPF consumption at 7 years old was and BMI-for-age z score at age 10

%UPF_energy proportion of energy from ultra-processed food to total energy intake, %UPF_eneergy proportion of intake from ultra-processed food to total energy intake, WC waist circumference, WHtR waist-to-height ratio, WHR waist-to-hip ratio, %BF percentage of body fat, LMI lean mass index, FMI fat mass index