Diet, Healthy, Food Selection
Conditions
Keywords
availability, labelling, food choice, socio-economic position
Brief summary
This study will be a 2x2 randomised controlled trial with information-based intervention (no labelling / labelling) and structural intervention (default proportion / increased proportion of lower energy density food items) as between-subject factors and energy density (kcal/g) of food purchases during an online supermarket-shopping task as dependent variable. This study will use an online supermarket platform developed to mimic an online supermarket website and participants will be asked to complete a shopping task using a pre-determined shopping list of 10 items.
Detailed description
See attached protocol documents.
Interventions
BEHAVIORALIncreased proportion of lower energy density items
The proportion of lower energy density vs. higher energy density items will be reversed (67% lower - 33% higher) relative to the default proportion condition (D and DL) (33% lower - 67% higher). Lower energy density items will be defined as lower energy density ≤ median of energy density distribution within a food category.
BEHAVIORALLabelling
When energy density of an item ≤ median of ED distribution within a food category, healthier choice badges will be added to the food item pictures on the online supermarket. Instructions when logging-into the platform will introduce the badges to the participants: In the online supermarket, the green tick allows you to see which products (e.g. muesli) in each product category (e.g. cereals) are healthier choices with fewer calories per gram than most other products in the same category.
Sponsors
University of Liverpool
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* United Kingdom residents * Aged ≥ 18 years * Fluent in English * Have access to a computer and Internet * Responsible for a substantial proportion of household grocery shopping
Exclusion criteria
* Unable to provide informed consent and to comply with the study requirements * Any dietary restriction (vegetarian, vegan, gluten-free, sugar-free, dairy or lactose free, food allergy, other)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Mean ED of the food items purchased (kcal/100g) | 20 minutes (the time frame denotes time taken to make the food shopping task online and there is no follow up) | Calculated as the sum of the energy of the purchased items (kcal) divided by the sum of their weight (g) and multiplied by 100. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Total energy of the food items purchased (kcal) | 20 minutes (the time frame denotes time taken to make the food shopping task online and there is no follow up) | Calculated as the sum of the energy of the purchased items (kcal) |
| Energy from total sugar (% of total energy) | 20 minutes (the time frame denotes time taken to make the food shopping task online and there is no follow up) | Calculated as the percentage of total energy of the purchased items from total sugar |
| Energy from saturated fatty acids (SFA) (% of total energy) | 20 minutes (the time frame denotes time taken to make the food shopping task online and there is no follow up) | Calculated as the percentage of total energy of the purchased items from SFA |
| Proportion of lower energy density food items in the basket of foods purchased | 20 minutes (the time frame denotes time taken to make the food shopping task online and there is no follow up) | Lower energy density items will be defined as ≤ median of energy density distribution within a food category |
| Cost (GPB) | 20 minutes (the time frame denotes time taken to make the food shopping task online and there is no follow up) | Calculated as the sum of the prices of the purchased items |
| Salt content (g/100g) | 20 minutes (the time frame denotes time taken to make the food shopping task online and there is no follow up) | Calculated as the sum of the salt content of the purchased items (g) divided by the sum of their weight (g) and multiplied by 100. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Validity | 5 minutes (the time frame denotes time taken to fill in the debriefing questionnaire and there is no follow up) | Mean of item I would normally buy \[the 10 items on the shopping list\] for all the food items coded as: 1 = Never; 2 = Very rarely; 3 = Rarely; 4 = Occasionally; 5 = Frequently; 6 = Very frequently. |
| Kcal influence | 5 minutes (the time frame denotes time taken to fill in the debriefing questionnaire and there is no follow up) | Answer to the item The choices I made during online shopping were influenced by how many calories I thought were in the options available. coded as: 1 = Strongly disagree; 2 = Disagree; 3 = Slightly disagree; 4 = Neutral; 5 = Slightly agree; 6 = Agree; 7 = Strongly agree |
Countries
United Kingdom
Outcome results
None listed