Altering the Availability of Healthier vs. Less Healthy Items in Vending Machines

University of Cambridge

Status: Completed

Conditions: Healthy Diet

Treatments: Behavioral: Availability of healthier vs. less healthy foods

Study type: Interventional

Funder types: Other

Identifiers

NCT03252158

PRE.2017.029

Details and patient eligibility

About

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.

Enrollment: 10 patients

Sex: All

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• All vending machines at one UK hospital selling standard-fare (i.e. not healthier alternatives) cold beverages and snack foods

Exclusion criteria

• Healthier alternative vending machines; vending machines selling hot drinks or meals

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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10 participants in 2 patient groups

Decrease less healthy item availability

Experimental group

Description:

Intervention: Availability of healthier vs. less healthy foods Remove less healthy items in 20% of slots, then fill the empty slots with healthier items.

Treatment:

Behavioral: Availability of healthier vs. less healthy foods

Decrease healthier item availability

Experimental group

Description:

Intervention: Availability of healthier vs. less healthy foods Remove healthier items in 20% of slots, then fill the empty slots with less healthy items.

Treatment:

Behavioral: Availability of healthier vs. less healthy foods