An interventional study of Availability of healthier vs. less healthy foods in Healthy Diet, sponsored by University of Cambridge. Completed at 1 site in United Kingdom. Per ClinicalTrials.gov, last updated 2018-05-03.
Sponsored by University of Cambridge · Not applicable, Interventional, and Basic science
Background: While there is some evidence that increasing the range of healthier foods and drinks and/or decreasing the range of less healthy options may increase healthier choices, more work is needed to establish the reproducibility of any effect. The current study aims to investigate the impact of altering the availability of healthier and less healthy foods and cold beverages in hospital vending machines.
Methods: An adapted multiple treatment reversal design will be used, in which all standard vending machines serving snack foods and/or cold beverages in one hospital in England change the number of slots containing (i) less healthy items and (ii) healthier items over eight 4-week periods. Changes will take place in a two-step process whereby decreases are implemented in a separate study period prior to increases in the contrasting food group. Following a 4-week baseline period, all vending machines will be standardised to have 75% healthier drinks and/or 25% healthier snacks (study period 1). Vending machines (n=9) will be randomly allocated to the order in which they: (1) decrease less healthy foods and increase healthier foods or (2) decrease healthier foods and increase less healthy foods (study periods 2\&3 and 5\&6). After each decrease-increase pair, machines will return to the standardised 75% healthier drinks and 25% healthier snacks (study periods 4 and 7). Sales data will be obtained via records of machine restocking.
Planned Analysis: The impact of the availability intervention will be assessed in separate linear mixed models for cold drinks and snacks, examining the impact on total energy (kcal) purchased, per restocking interval, with random effects for vending machine.
Exclusion Criteria:
Intervention: Availability of healthier vs. less healthy foods Remove less healthy items in 20% of slots, then fill the empty slots with healthier items.
Behavioral: Availability of healthier vs. less healthy foods
Intervention: Availability of healthier vs. less healthy foods Remove healthier items in 20% of slots, then fill the empty slots with less healthy items.
Behavioral: Availability of healthier vs. less healthy foods
Altering the number of slots containing (a) healthier and (b) less healthy foods or beverages in hospital vending machines. Changes follow a 2-step process whereby decreases are implemented in a separate study period prior to increases in the contrasting group. Following a 4-week baseline period, all vending machines will be standardised to have 75% healthier drinks and/or 25% healthier snacks (study period 1). Vending machines will be randomly allocated to the order in which they: (1) decrease less healthy foods and increase healthier foods or (2) decrease healthier foods and increase less healthy foods (study periods 2\&3 and 5\&6). After each decrease-increase pair, machines will return to the standardised 75% healthier drinks / 25% healthier snacks (study periods 4 and 7).
Energy purchased
Energy purchased (kcal) per restocking interval from intervention (standard-fare) vending machines
Time frame: Restocking interval (between 2-4 days; restocking occurs on set weekdays for each machine, to match usual restocking)
Number of items sold
Number of items sold per restocking interval from intervention (standard-fare) vending machines
Time frame: Restocking interval (between 2-4 days; restocking occurs on set weekdays for each machine, to match usual restocking)
Energy purchased (healthier alternative machines)
Energy purchased (kcal) per restocking interval from non-intervention (healthier-fare) vending machines
Time frame: Restocking interval (between 2-4 days; restocking occurs on set weekdays for each machine, to match usual restocking)
Number of items sold (healthier alternative machines)
Number of items sold per restocking interval from non-intervention (healthier-fare) vending machines
Time frame: Restocking interval (between 2-4 days; restocking occurs on set weekdays for each machine, to match usual restocking)
This study is completed, as verified in May 2018. You cannot join it, but the record below documents what was studied.
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University of Cambridge