Increased Proportion of Lower Energy Density Items vs. Nutritional Labelling at an Online Supermarket
- Conditions
- Diet, HealthyFood Selection
- Interventions
- Behavioral: LabellingBehavioral: Increased proportion of lower energy density items
- Registration Number
- NCT04340791
- Lead Sponsor
- University of Liverpool
- 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.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 1000
- 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
- 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)
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Default proportion & labelling Labelling When energy density of a food item ≤ median of energy density distribution within a food category, "healthier choice" badges will be added to the food item pictures on the online supermarket. Instructions will introduce the badges to the participants as "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." Increased proportion & labelling Labelling The proportion of lower energy density items vs. higher energy density items will be reversed (67% lower - 33% higher) relative to the default proportion condition (33% lower - 67% higher). Lower energy density items will be defined as lower ED ≤ median of ED distribution within a food category. When energy density of a food item ≤ median of energy density distribution within a food category, "healthier choice" badges will be added to the food item pictures on the online supermarket. Instructions will introduce the badges to the participants as "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." Increased proportion & no labelling Increased proportion of lower energy density items The proportion of lower energy density items vs. higher energy density items will be reversed (67% lower - 33% higher) relative to the default proportion condition (33% lower - 67% higher). Lower energy density items will be defined as lower ED ≤ median of ED distribution within a food category. Increased proportion & labelling Increased proportion of lower energy density items The proportion of lower energy density items vs. higher energy density items will be reversed (67% lower - 33% higher) relative to the default proportion condition (33% lower - 67% higher). Lower energy density items will be defined as lower ED ≤ median of ED distribution within a food category. When energy density of a food item ≤ median of energy density distribution within a food category, "healthier choice" badges will be added to the food item pictures on the online supermarket. Instructions will introduce the badges to the participants as "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."
- Primary Outcome Measures
Name Time Method 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 Outcome Measures
Name Time Method 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
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 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
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.
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
Trial Locations
- Locations (1)
University of Liverpool
🇬🇧Liverpool, Merseyside, United Kingdom