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Completed

NCT Number: NCT04340791

Increased Proportion of Lower Energy Density Items vs. Nutritional Labelling at an Online Supermarket

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.

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Key information

Conditions

Diet, Healthy Behavior Feeding Behavior Food Preferences Food Selection

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Liverpool

Liverpool, Merseyside, L69 7ZA, United Kingdom

About this study

See attached protocol documents.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Increased proportion of lower energy density items

Behavioral

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.

Labelling

Behavioral

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."

Primary outcomes

  1. Mean ED of the food items purchased (kcal/100g)

    Time frame: 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 outcomes

  1. Total energy of the food items purchased (kcal)

    Time frame: 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)

  2. Energy from total sugar (% of total energy)

    Time frame: 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

  3. Energy from saturated fatty acids (SFA) (% of total energy)

    Time frame: 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

  4. Salt content (g/100g)

    Time frame: 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.

  5. Proportion of lower energy density food items in the basket of foods purchased

    Time frame: 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

  6. Cost (GPB)

    Time frame: 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

Other outcomes

  1. Validity

    Time frame: 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.

  2. Kcal influence

    Time frame: 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

Sponsors and collaborators

Lead sponsor

University of Liverpool

Other

Registry information

Official study title

Effectiveness of Information-based Versus Structural Interventions on Food Choices by Socioeconomic Position: a Randomized Controlled Trial in an Experimental Online Supermarket

Important dates

Study start
2020
Primary completion
2020
Study completion
2020
First posted
Apr 10, 2020
Registry last updated
Nov 3, 2020

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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