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

University of Liverpool

Status: Completed

Conditions: Food Selection; Diet, Healthy

Treatments: Behavioral: Increased proportion of lower energy density items; Behavioral: Labelling

Study type: Interventional

Funder types: Other

Identifiers

NCT04340791

803194 1B3

Details and patient eligibility

About

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.

Full description

See attached protocol documents.

Enrollment: 1,000 patients

Sex: All

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

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)

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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1,000 participants in 4 patient groups

Default proportion & no labelling

No Intervention group

Description:

No intervention: Default proportion condition (33% lower energy density items - 67% higher energy density items). Lower energy density items will be defined as lower ED ≤ median of ED distribution within a food category. No labelling.

Default proportion & labelling

Experimental group

Description:

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."

Treatment:

Behavioral: Labelling

Increased proportion & no labelling

Experimental group

Description:

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.

Treatment:

Behavioral: Increased proportion of lower energy density items

Increased proportion & labelling

Experimental group

Description:

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."

Treatment:

Behavioral: Labelling

Behavioral: Increased proportion of lower energy density items