Healthy Diet
Conditions
Brief summary
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.
Interventions
BEHAVIORALAvailability 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).
Sponsors
Oxford University Hospitals NHS Trust
University of Cambridge
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
An adapted multiple treatment reversal design will be used, in which the number of slots containing (i) less healthy items and (ii) healthier items are altered over eight 4-week periods. Vending machines will be randomly allocated to one of two groups: (1) decreasing less healthy foods first or (2) decreasing healthier foods first.
Eligibility
Sex/Gender
ALL
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Energy purchased | Restocking interval (between 2-4 days; restocking occurs on set weekdays for each machine, to match usual restocking) | Energy purchased (kcal) per restocking interval from intervention (standard-fare) vending machines |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Number of items sold | Restocking interval (between 2-4 days; restocking occurs on set weekdays for each machine, to match usual restocking) | Number of items sold per restocking interval from intervention (standard-fare) vending machines |
| Energy purchased (healthier alternative machines) | Restocking interval (between 2-4 days; restocking occurs on set weekdays for each machine, to match usual restocking) | Energy purchased (kcal) per restocking interval from non-intervention (healthier-fare) vending machines |
| Number of items sold (healthier alternative machines) | Restocking interval (between 2-4 days; restocking occurs on set weekdays for each machine, to match usual restocking) | Number of items sold per restocking interval from non-intervention (healthier-fare) vending machines |
Countries
United Kingdom
Outcome results
None listed