Cravener 2015.

Study characteristics
Methods	Study design RCT Funding "College of Health and Human Development (Pennsylvania State University)"
Participants	Description Children aged 3 to 5 years with low vegetable intake N (randomised) 24 children Age Child (mean): intervention = 3.8 years, control = 4.0 years Parent: not reported % female Child: intervention = 50%, control = 50% Parent: not reported SES and ethnicity “The majority of the participants were white (92%)” Parent: “83.3% of mothers and 82.6% of fathers reported graduating from college and/or graduate school.” Inclusion/exclusion criteria Inclusion criteria: children aged 3 ‐ 5 years, categorised as “at risk for obesity” based on family history, defined as having at least one parent with a body mass index > 25 and consuming 2 or fewer servings of vegetables per day (according to parent report) Exclusion criteria: pre‐existing medical conditions (including relevant food allergies) Recruitment “recruited via flyers posted around the university community and in local newspapers and websites (e.g. Craigslist).” Recruitment rate Not reported Region Pennsylvania (USA)
Interventions	Number of experimental conditions 2 Number of participants (analysed) Intervention = 12, control = 12 Description of intervention “children in the treatment group (n=12) received vegetables packaged in containers decorated with their four favorite cartoon characters (selected on the first visit) and granola bars in generic packaging. All vegetable packages contained sticker incentives and children could collect stickers on a special game board and trade them for small prizes at the end of the study. This was done to simulate the concept of promotions that often come with packaged foods. Parents were in charge of deciding when children had eaten enough of a vegetable to be awarded the sticker for their game boards.” Duration 2 weeks Number of contacts Parents were instructed “to offer children a choice between either a vegetable or granola bar for at least three snacks and/or meals per day.” Setting Home and lab Modality Face‐to‐face Interventionist Parents Integrity “To assess compliance, parents completed daily checklists across the intervention to report when vegetables and granola bars were offered and record what children selected. In addition, parents could also report additional comments on these checklists to report other concerns or deviations. Parents were also responsible for keeping daily food diaries for children (data to be reported elsewhere). These logs were reviewed with parents during weekly home visits to assess progress.” Date of study Recruitment August 2012 to June 2013 Description of control “children in the control group (n=12) received weekly supplies of generic‐packaged vegetables and granola bars presented as part of a free choice at meals and snacks..”
Outcomes	Outcome relating to children's fruit and vegetable consumption Children’s intake of vegetables (grams), “Intake was measured as the difference between pre‐ and post‐weights of the foods provided.” Outcome relating to absolute costs/cost effectiveness of interventions Not reported Outcome relating to reported adverse events Not reported Length of follow‐up from baseline 4 weeks Length of follow‐up postintervention 1 week Subgroup analyses None Loss to follow‐up There was no loss to follow‐up Analysis Sample size calculation was performed.
Notes	First reported outcome (broccoli intake grams/day) at the longest follow‐up (4‐week follow‐up) was extracted for inclusion in meta‐analysis Sensitivity analysis ‐ primary outcome: fruit or vegetable intake is primary outcome
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomly assigned to condition using a random‐number generator.
Allocation concealment (selection bias)	Unclear risk	There is no information provided about allocation concealment and therefore it is unclear if allocation was concealed
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Outcome group: All/ Children’s vegetable and granola bar intake Families and researchers were not blinded to condition but it is unlikely that this influenced child consumption
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Outcome group: All/ Children’s vegetable and granola bar intake Families and researchers were not blinded to condition and it is unclear if this had an impact on the weighing of food. The extent to which parents were compliant with instructions to return all leftovers is unknown
Incomplete outcome data (attrition bias) All outcomes	Low risk	Outcome group: All/ 100% retention rate and so risk of attrition bias is very low
Selective reporting (reporting bias)	Unclear risk	There is no study protocol therefore it is unclear if there was selective outcome reporting
Other bias	Low risk	Contamination bias that could threaten the internal validity is unlikely to be an issue