Table 2.

Details regarding dietary assessment methods and procedures of the included studies

Author. Year (Country)	Reporter of dietary intake	Dietary assessment method	EI analysis details	Equipment, instructions or specialist involvement to improve dietary assessment accuracy
Bandini et al. 1990 (USA) [21] and Bandini et al. 1999 (USA) [22] (considered as a subset of the above article as the data are from the same study)	Adolescent	2-week FR	Nutrient Data Base for Standard Reference (USDA) supplemented with the manufacturer’s data	• Food models, measuring cups and spoons were used to instruct participants on how to estimate portion sizes at the beginning of the study. Participants were then given a standardised FR, measuring cups and spoons to use at home• One meal consumed and entry completed at research appointment and checked to ensure accuracy• Participants phoned three to four times during 2 week period to review FR• Participants paid to encourage adherence. Money deducted for each day they did not keep a FR• Diet records were coded for nutrient analysis by a trained nutritionist
Börnhorst et al. 2014 (Belgium, Spain and Sweden) [23]	Parent	2× computerised 24 h DR (Self-Administered Children and Infants Nutrition Assessment—SACINA)	Country-specific food composition tables	• Photos, standard portions, customary packing size and foods in pieces or slices were displayed on the screen to assist serving size estimation,• Chronological questions related to daily activities embedded within the 24 h DR• Fieldwork personnel supervised parent completion of 24 h DR• School meals were assessed either through parents or by fieldwork personnel via direct observation using pre-defined recording sheets
Champagne et al. 1998 (USA) [24]	Combined child and parent	8-Day FR	Dietary analysis software—Moore’s Extended Nutrient (MENu) database (Baton Rouge, La, USA), which is based on USDA Nutrient Data Base for Standard Reference (1993, USA), USDA Nutrient Data Base for Individual Food Intake Surveys (1992, USA) and the Extended Table of Nutrient Values (1991, USA).	• FR instruction summary sheet, guides to determining portion size, examples of completed FR and food description checklists. Family recipes requested, as well as food labels where possible• Children and parents received training on keeping a FR• A nutritionist recorded lunch time intake at school for all children
Singh et al. 2009 (USA) [25]	Adolescent	Food intake recorded via FR for 9 days (6 consecutive days prior to DLW administration, and further recording for 3 days at 1 week after DLW measurement period ceased)	Computerised database and analysis programme (Nutrition Data System for Research (NDS-R) software, Version 5.0, the University of Minnesota, USA)	• Standardised form used, each participant given instructions with illustrations of food and portion sizes, and encouraged to record items in household measures, as well as draw pictures to indicate portion size• Dietitian reviewed records with each subject in between 6 and 3 day data collection periods
Vasquez et al. 2006 (Chile) [26]	Parent proxy and trained nutritionist	3-Day FR. Two week days at day-care centre, one weekend day at home	Computerised programme based on Chilean food composition table	• Food consumed during day-care centre hours was recorded by a trained nutritionist, and calculated by weighing each meal and leftovers. Food at day-care centres were prepared by private caterers and food components were known in advance and chemical composition provided by food suppliers• Parents given paperwork to record all food eaten at home on day-care centre weekdays. This record was reviewed by the same nutritionist as above each morning• For the weekend day, parents were interviewed on the following Monday to review the record
Waling and Larsson. 2009 (Sweden) [27]	Combined parent and child	DHI covering the previous 2 weeks	Dietist XP version 3.0 dietary analysis programme—based on the 2008 Swedish food composition database	• List of school meals, description of portion sizes, food portion photographs, household measurements, standards weights of food items and bags of rice in different volumes• Primary author or trained nutritionist completed the interview

24 h DR 24 h dietary recall, DHI diet history interview, DLW doubly labelled water, EI energy intake, FR food record, USDA United States Department of Agriculture