De Bock 2012.

Study characteristics
Methods	Study design: cluster‐RCT Intervention period: 6 months Follow‐up period (post‐intervention): nil Differences in baseline characteristics: reported Reliable outcomes: reported Protection against contamination: NR Unit of allocation: individual Unit of analysis: individual
Participants	N (control baseline) = 183 N (control follow‐up) = NR (N = 202 intervention + control at follow‐up) N (intervention baseline) = 194 N (intervention follow‐up) = NR Setting (and number by study group): 18 preschools (10 preschools, N = 194 children in intervention group; 8 preschools, N = 183 children in control group) Recruitment: had applied to participate in the nutritional intervention module of a state‐sponsored health promotion programme ‘Komm mit in das gesunde Boot’ Geographic region: 3 areas of Baden‐Württemberg in South West Germany Percentage of eligible population enrolled: 78% of preschools, 80% participants Mean age: intervention + control: 4.26 ± 0.78 Sex: intervention + control: 46.8% female
Interventions	To assess the effects of a preschool‐based nutritional intervention on both behavioural outcomes, like children’s fruit, vegetable and water consumption, and anthropometric measures. 6‐month intervention administered once weekly by a nutrition expert consisting of joint meal preparation and activities for children and parents such as tasting and preparing nutritious, fresh foods. Fifteen 2‐hour sessions once weekly over a period of 6 months. 10 modules only targeted children, another 5 parents and children, or parents exclusively, involving parents by targeting them alone (discussions on parents’ modelling role and nutritional needs of children) or together with their children. Intervention activities consisted of familiarising with different food types and preparation methods as well as cooking and eating meals together in groups of children, teachers and parents. One session additionally focused on healthy drinking behaviours. Models for healthy eating within the intervention include: use of nutrition experts play acting with 'pirate dolls' used as props enjoying fruit and vegetables active parental involvement involvement of other preschool peers Waiting list control DIet intervention vs control
Outcomes	Outcome measures Primary outcome: fruit and vegetable intake, ?PA Secondary outcomes: BMI, skinfold thickness, waist‐to‐height ratio, consumption of water and sugared drinks Process evaluation: reported (fidelity)
Implementation‐related factors	Theoretical basis: Social Learning theory and Exposure theory Resources for intervention implementation: NR Who delivered the intervention: reported PROGRESS categories assessed at baseline: child: gender, race/ethnicity; parent: education PROGRESS categories analysed at outcome: NR Outcomes relating to harms/unintended effects: NR Intervention included strategies to address diversity or disadvantage: NR Economic evaluation: NR
Notes	Funding: this work was supported by a grant from the Baden‐Württemberg Stiftung. F.D.B. is supported by the European Social Fund and by the Ministry of Science, Research and the Arts Baden‐Württemberg. This paper focuses on the nutritional intervention element but protocol reports that PA is a primary outcome. On average, 23.1 (SD 12.1) children participated regularly in the lessons; 16.5 (SD 9.5) parents present at the parents’‐only and parent and children’s sessions. Reports that sustainability measurements not available from all participating preschools.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Stratified the recruited preschools before randomisation to balance aggregate preschool social background and immigrant proportion
Allocation concealment (selection bias)	Unclear risk	NR
Blinding (performance bias and detection bias) All outcomes	Low risk	Study personnel were blinded to group assignment
Incomplete outcome data (attrition bias) All outcomes	High risk	58% of the children provided both pre and post‐intervention measurements
Selective reporting (reporting bias)	Unclear risk	Protocol/trial registration documents were unavailable
Other bias	Low risk	No additional threats to validity
Other bias‐ timing of recruitment of clusters	Low risk	Figure shows recruitment happened prior to randomisation Quote: "we stratified the recruited pre‐schools before randomization to balance aggregate pre‐school social background and immigrant proportion"