Cunha 2013.

Study characteristics
Methods	Study design: cluster‐RCT Intervention period: 9 months Follow‐up period (post‐intervention): nil Differences in baseline characteristics: reported Reliable outcomes: reported (for BMI) Protection against contamination: NR Unit of allocation: class Unit of analysis: individual accounting for clustering
Participants	N (controls baseline) = 281 N (controls follow‐up) = 282 N (interventions baseline) = 293 N (interventions follow‐up) = 277 Setting (and number by study group): 20 classes in 20 schools (N = 20 classes, 1 class in each school, N = 10 intervention classes and 293 participants and N = 10 control classes and 281 participants) Recruitment: selected 20 schools from 35, no further details Geographic region: municipality of Duque de Caxias, Rio de Janeiro, Brazil Percentage of eligible population enrolled: 98% Mean age: intervention: 11.2 ± 1.3; control: 11.2 ± 1.3 Sex: intervention: 47.7% female; control: 48.6% female
Interventions	To evaluate the effectiveness of an intervention involving families and teachers to prevent excessive weight gain among adolescents in Brazil Students attended 9 nutritional education sessions (1/month for 9 months) during the 2010 academic year provided by external trained nutritionists. Encouraging students to change their eating habits and food consumption via trained nutritionists giving monthly 1‐h sessions in the classrooms on the following themes: healthy eating native Brazilian eating habits excessive sugar in processed food marriage of the rice and beans the beauty of fruits super water: a super‐hero cookies mini‐market food advertisements Each session included: activities, related to the subject, to be conducted at the school folders explaining the intervention programme and suggesting the participation of the family, such as reducing purchase of sodas and increasing the purchase of fruit, to be sent home strategies for reinforcement of themes by the teachers, using exercises prepared for this purpose, such as specific popular histories or maths games a set of messages sent to families in the form of illustrated booklets and recipes. Parents/guardians and teachers received information on the same subjects. The control group received a 1‐hour section of orientation on general health and advice on eating, at the end of the study Diet intervention vs control
Outcomes	Outcome measures Primary outcome: BMI Secondary outcomes: body fat, percentage overweight/obese, dietary intake Process evaluation: reported (compliance)
Implementation‐related factors	Theoretical basis: TTM Resources for intervention implementation: reported Who delivered the intervention: reported PROGRESS categories assessed at baseline: child: race/ethnicity PROGRESS categories analysed at outcome: NR Outcomes relating to harms/unintended effects: NR Intervention included strategies to address diversity or disadvantage: NR (area selected is one of the poorest in Brazil) Economic evaluation: NR
Notes	NCT01046474 Funding: this work was supported by Foundation of Support of Research of the State of Rio de Janeiro ‐ FAPERJ (E261029422008); National Counsel of Technological and Scientific Development ‐ CNPQ (474288/2009‐9); Pan American Health and Education Foundation ‐ PAHEF. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. 14% of final sample were participants who entered the study after random allocation; schools selected that were in low violence areas.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Each pair in the ranking sequence was randomly drafted with 1 class being assigned to the experimental group and 1 to the control group. Randomisation process was conducted by the investigators.
Allocation concealment (selection bias)	Low risk	Opaque envelopes
Blinding (performance bias and detection bias) All outcomes	High risk	NR
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Very low attrition (< 5%) however 14% of final sample were participants who entered the study after random allocation
Selective reporting (reporting bias)	Low risk	Protocol/trial registration document seen. All outcomes reported
Other bias	Low risk
Other bias‐ timing of recruitment of clusters	Unclear risk	Figure shows 14% of final sample were participants who entered the study after random allocation