Whatley Blum 2007.

Study characteristics
Methods	Trial name: no trial name Study design: non‐randomised Intervention duration: 1 year Length of follow‐up from baseline: approximately 1 year between baseline and follow‐up data collection spring 2004 (baseline data collection) to spring 2005 (follow‐up data collection). Recruitment date not provided. Differences in baseline characteristics: intervention schools had more students eligible for free/reduced‐price meal (32.9%) compared to controls (20.0%). Unit of allocation: school Unit of analysis: school
Participants	School type: public high schools Region: Maine, USA Demographic/socioeconomic characteristics: % students eligible for free/reduced‐price meal: control = 20.0%, intervention = 32.9%. No further details of student demographics provided. Inclusion/exclusion criteria Inclusion ‐ Participation in NSLP. ‐ Offered an à la carte programme. ‐ Have ≥ 1 snack and 1 beverage vending machine accessible to students. Exclusion: not provided Number of schools allocated: 7 Numbers by trial group n (controls baseline) = 3 n (controls follow‐up) = 3 n (interventions baseline) = 4 n (interventions follow‐up) = 4 Recruitment: electronic informational letter sent from the Maine Department of Education to all 150 superintendents. 50 Interested schools were screened by telephone. Recruitment rate: 7 schools expressed interest and met inclusion criteria (denominator unknown).
Interventions	Number of experimental conditions: 2 (1 intervention, 1 control) Policies, practices or programmes targeted by the intervention Implementing low‐fat, low‐sugar and portion‐controlled guidelines in à la carte and vending (snack and beverage) programmes. Implementation strategies EPOC: educational outreach visits ‐ Visits by research staff to each school's food and beverage supplier to identify items that met the low fat, low sugar guidelines. EPOC: educational materials ‐ Suppliers who stocked vending machines were given lists of the available low fat, low sugar items (expected to stock from the autumn 2004) and letters sent home to parents and students informing them of changes incentives. Banners were also displayed to promote healthier foods and taste testing was conducted. EPOC: clinical practice guidelines ‐ Modification of recipes and preparation techniques by research and food service personnel. EPOC: procurement and distribution of supplies ‐ Food service directors were given lists of available products/vendors that met low fat, low sugar guidelines. EPOC: educational meetings ‐ Presentations describing low fat, low sugar guideline made to school administrations, faculty, staff or a combination of these. EPOC: external funding ‐ USD1500 allocated annual to school liaison personnel. EPOC: local consensus process ‐ A committee at each school site was created. A liaison identified at each school was responsible for establishing the committee to promote the healthy changes in the vending machines and à la carte menus at their schools. Expectations for the committees were discussed in detail with each school liaison; these expectations included recruitment of representatives from all stakeholder groups — school administration, faculty, students, parents and food service personnel — and the completion of ≥ 4 activities over the course of the school year to promote the healthy changes. EPOC: other ‐ Early communication between the project team and schools began in 2004 as a means to obtain the co‐operation of school administration, and meet food service personnel. Theoretical underpinning: not reported Description of control: made no changes to à la carte and vending machine programmes for 1 school year.
Outcomes	Outcome relating to the implementation of school service policies, practices or programmes ‐ % items meeting nutrient (low fat, low sugar) criteria in à la carte ‐ % items meeting nutrient (low fat, low sugar) criteria in snack vending ‐ % items meeting nutrient (low fat, low sugar) criteria in beverage vending ‐ % items meeting nutrient (low fat, low sugar) AND proportion criteria in à la carte ‐ % items meeting nutrient (low fat, low sugar) AND proportion criteria in snack vending ‐ % items meeting nutrient (low fat, low sugar) AND proportion criteria in beverage vending Data collection method: trained personnel visited the school on 5 consecutive non‐randomised days at baseline and follow‐up. Observation and recording of items sold was taken at breakfast and lunch at cafeterias. Vending machine data included: number of machines, items and nutritional information completed on the same day as nutritional observation. Validity of method: not reported; however, methods considered objective Outcome relating to cost: not reported Outcome relating to adverse consequences: not reported Outcome relating to child diet, PA or weight status: consumption of sugar sweetened beverages Data collection method: food frequency questionnaire: subjects were asked to complete the youth food frequency questionnaire for what they ate and drank over the past 30 days. Validity of method: the youth food frequency questionnaire has been shown to be valid in youth (defined as 9–18 years of age) with mean correlation of r = 0.49 for food groups from the youth food frequency questionnaire compared with 3 × 24‐hour recalls.
Notes	Research funding: grant from the CDC (03022). Conflicts of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Non‐randomised design. High risk of selection bias as high schools volunteered into the intervention or control group.
Allocation concealment (selection bias)	High risk	Non‐randomised design. High schools volunteered into an experimental group, therefore, high risk of bias as no concealment of allocation.
Blinding of participants and personnel (performance bias) Implementation outcome	High risk	Outcome group: high schools volunteered as intervention or control, therefore, participants and personnel were not blind to allocation and there was a high risk of performance bias.
Blinding of outcome assessment (detection bias) Implementation outcome	Unclear risk	Outcome group: trained personnel visited each school to conduct observations. There was no information provided about whether these personnel were blinded to group allocation (i.e. may have conducted observations only and be unaware of the purpose of the study) and, therefore, the risk of detection bias was unclear.
Incomplete outcome data (attrition bias) Implementation outcome	Low risk	Outcome group: no schools dropped out and this study conducted observations of à la carte and vending programmes in schools.
Selective reporting (reporting bias)	Unclear risk	No study protocol, therefore, it was unclear if there was selective outcome reporting.
Other bias	Low risk	Appeared free from other bias.
Potential confounding	Unclear risk	The characteristics of the school and food environments were presented for the control and intervention groups (i.e. number of students, percentage of students eligible for free/reduced‐price meal, closed campus policy during lunch, offered à la carte breakfast). However, given this was a quasi‐experimental trial with no random allocation, it was unclear if all potential confounders were measured.
Overall risk of bias assessment	Unclear risk	Most domains were at low or unclear risk of bias.