Witt 2012.

Study characteristics
Methods	Study design: cluster‐RCT Length of follow‐up from baseline: 3 months Unit of allocation: centre Unit of analysis: child
Participants	Service type: centre‐based Operation: all classrooms offered half‐day or full‐day care. All classrooms participated in the child and adult care food program and provided meals and snacks to children. Country (region): USA (not reported) Country income classification: high Low‐SES sample: yes Population description: 15/17 of the classrooms were from the Boise School District’s ECEC programme. Inclusion criteria: not reported Exclusion criteria: not reported Number of services randomised: 17 (10 intervention, 7 control) Number of children randomised: 263 (165 intervention, 98 control) Characteristics Children Age: the majority of children were 4 or 5 years old. Gender (% female): 47% Ethnicity: not reported Parents Age (years): not reported Gender (% female): not reported Ethnicity: not reported Parent/family SES: not reported ECEC staff (lead teachers) Age (years): not reported Gender (% female): 94% Ethnicity: not reported Service/ECEC staff SES: not reported Method of recruitment: not reported Missing data/dropout: unclear Reasons for dropout: either absent or unenrolled from the centre at follow‐up assessments Characteristics of dropouts: not reported
Interventions	Programme name: Color Me Healthy Number of conditions: 1 intervention, 1 control Intervention duration: 6 weeks Intervention setting: ECEC Intervention strategies: Health curriculum Children Education: 12 circle‐time lessons and 6 imaginary trips, using colour, music and exploration of the senses to teach children about healthy eating and physical activity. The majority of the Color Me Healthy circle‐time lessons focus on fruits and vegetables of different colours. Ethos and environment Children Exposure: several of the lessons provide opportunities for children to try (taste) fruits and vegetables. The imaginary trips allowed children to be physically active and role‐play eating nutritious food. ECEC staff Training: lead teachers attended a training session that was held prior to programme implementation. The teachers learned about the curriculum and were instructed on how to teach each lesson and imaginary trip. Materials: a ‘‘toolkit’’ that includes a teacher’s guide, 4 sets of picture cards, classroom posters, a music CD that contains 7 original songs, a hand stamp, and reproducible parent newsletters. Most of the kit materials emphasise fruits and vegetables of different colours. Partnerships Families Resources: 6 interactive take‐home activities for parents and children to complete. Parent newsletters. Intensity of intervention: 2 circle‐time lessons and 1 imaginary trip were taught to the children each week for 15‐30 min; staff training (frequency and duration not reported) Intervention delivered by: ECEC staff Modality: face‐to‐face, written Theoretical basis: not reported Description of control: usual care
Outcomes	Outcomes relating to child dietary intake: Fruit snack intake, pineapple intake, cantaloupe intake, strawberry intake, purple grapes intake, vegetable snack intake, carrot intake, cherry tomato intake, celery intake, broccoli intake, Ritz cracker intake, graham cracker intake Number of participants analysed: Intervention baseline: 70‐83 Intervention follow‐up: 70‐83 Control baseline: 52‐70 Control follow‐up: 52‐70 Data collection measure: plate weight before and after Data collector: not reported Validity of measures used: not reported Outcomes relating to child physical measures: not reported Outcome relating to child language and cognitive performance: not reported Outcome relating to child social/emotional measures: not reported Outcome relating to child quality of life: not reported Outcome relating to cost: not reported Outcome relating to adverse consequences: not reported
Notes	Funding source: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	17 preschool classrooms were randomly assigned to 1 of 2 groups. The sequence generation procedure was not described.
Allocation concealment (selection bias)	Unclear risk	No information on the method of allocation concealment reported
Blinding of participants and personnel (performance bias) Diet outcomes	Unclear risk	No clear blinding of participants and personnel to study allocation, however teachers were instructed to avoid commenting on the snack and avoid encouraging children to eat the snack during outcome assessment.
Blinding of outcome assessment (detection bias) Diet outcomes	Low risk	Blinding not reported, however children's consumption was measured by weighing the fruit and vegetable snacks before and after intake. The outcome measurement is not likely to be influenced by lack of blinding.
Incomplete outcome data (attrition bias) Diet outcomes	High risk	Data for fruit snacks were available for 83 (50%) children in the intervention group and 70 (71%) children in the control group, while data for vegetable snacks were available for 70 (42%) children in the intervention group and 52 (53%) children in the control group. Although some reasons for loss provided, it is not known whether those reasons are exhaustive or equally distributed between treatment groups. Due to the magnitude of missing data and difference in the proportions of participants followed up between groups, the risk of bias was assessed as high.
Selective reporting (reporting bias)	Unclear risk	No prospective trial protocol or trial registration so it was unclear whether there was selective outcome reporting.
Recruitment bias	Unclear risk	It is unclear whether individuals were recruited to the study before or after randomisation of clusters.
Baseline imbalance	Unclear risk	Baseline differences between groups were not reported.
Loss of clusters	Unclear risk	Not reported
Incorrect analysis	Low risk	Study authors stated that "The study design was a 3‐level design: the first level was the repeated measures; the second level included child variables; and the third level included classroom and teacher variables."
Contamination	Unclear risk	No evidence to make assessment
Other bias	High risk	There is insufficient information to draw conclusions. Study authors stated that "Two hundred sixty‐three parents were invited to participate in the evaluation, and 38% (n=100) completed the initial surveys, which assessed changes in children’s fruit and vegetable consumption in the home environment and included a 3‐day food diary, food frequency questionnaire, and a general health survey. At follow‐up, 14% (n=38) of the parents had completed the surveys. Thus, there were not enough data to make substantive conclusions about changes in fruit and vegetable consumption in the home environment." No funding statement was provided. No conflict of interest statement was reported.