Food Stop: a population-based randomised trial assessing child and adult snack food intake in response to manipulated food quantity and snack box size

INTERVENTION: This cross‐sectional randomised controlled trial (RCT) took place within the Child Health CheckPoint (CheckPoint), nested within the established population‐representative birth‐cohort The Longitudinal Study of Australian Children (LSAC). CheckPoint (conducted in 2015) was a cross‐sectional physical and biomarkers module that was nested between the sixth (2014) and seventh (2016) waves of LSAC for the B‐cohort of children. Each child and one parent attended an Assessment Centre that moved around Australia; here they completed a circuit of 17 15‐minute health assessment stations (e.g. dental, bone, heart health assessments), of which the Food Stop study was one station. Because Food Stop was only included at the larger/main centres throughout Australia, ˜1300 families participated in Food Stop. This intervention tested the effect of manipulating snack box size and number of snack box portions on the snack food intake of 11‐12‐year‐old children and mid‐life adults. Each study child and their parent independently attended the Food Stop for a 15‐minute break from the other physical health assessments that were occurring within the CheckPoint Assessment Centre. Participants were randomly allocated to one of four experimental conditions (NB: random assignment was by day of participation, therefore the study child and their parent were assigned to the same condition, but participated separately to one another): Condition 1 (control): Small number of snack food portions, small snack box (18.0cm x 12.0cm x 5.0cm; volume 1080cm3) Condition 2: Small number of snack food portions, large snack box (19.5cm x 14.0cm x 56.5cm; volume 1774.5cm3) Condition 3: Large number of snack food portions, small snack box (18.0cm x 12.0cm x 5.0cm; volume 1080cm3) Condition 4: Large number of snack food portions, large snack box (19.5cm x 14.0cm x 56.5cm; volume 1774.5cm3) The random assignment schedule was generated by an independent statistician by day of participation in blocks of four CONDITION: Overconsumption of energy‐dense snack foods ; Nutritional, Metabolic, Endocrine PRIMARY OUTCOME: Grams and kilojoules of snack foods consumed during a standardised 15‐minute period, measured by weighing leftover items using food scales/balance (BSK500BSS) SECONDARY OUTCOME: Total sugar (g), fat (g), saturated fat (g), protein (g), carbohydrate (g), and sodium (mg) consumed during a standardised 15‐minute period, measured by weighing leftover items using food scales/balance (BSK500BSS) INCLUSION CRITERIA: Food Stop was part of the Child Health CheckPoint (CheckPoint), which was nested within the Birth‐cohort (B‐cohort) of the Longitudinal Study of Australian Children (LSAC). LSAC is the only nationally‐representative children’s longitudinal study in Australia. The study involves biennial data collection waves from two cohorts (B‐ and K‐cohorts) of population‐representative children and their parents. The CheckPoint study only recruited those children (age range 11‐12) and their midlife parents from LSAC’s B‐cohort who agreed to be contacted by the CheckPoint team (n=3513). Of the 3513 families that were invited to participate in CheckPoint, 1874 child‐parent dyads took part in CheckPoint throughout Australia.