None listed
Conditions
Brief summary
Following successful use in tobacco control, health warnings on food products and at point-of-sale have been proposed as a potential obesity prevention measure. This study aims to investigate the efficacy of food product health warnings for promoting healthy dietary decision making. Additionally, the study aims to investigate the degree to which two key health warning design factors (text-based health warnings versus text-and-graphic health warnings; health warnings featuring positively versus negatively framed messages) influence health warning efficacy. Ninety-six participants will be recruited to complete a mixed design dietary self-control experiment conducted as a single session. The experiment features four stages; the rating stage, the unprimed decision stage, the priming stage, and the primed decision stage. In the first stage, participants will be shown a selection of 100 common Australian snack foods (including chocolate, chips, cookies, fruit, nuts and vegetables) and asked to provide subjective health and taste ratings for each food item. In the unprimed (baseline) decision stage, participants will be shown half of the food items they rated in the first stage and asked to indicate which of these items they would like to eat at the end of the experiment. Prior to the priming stage, participants will be randomly allocated to one of five health warning format conditions; text-based, negative framing (n = 16); graphic, negative framing (n = 16); text, positive framing (n = 16); graphic, positive framing (n = 16); control group (n = 32). During the priming stage, participants will be exposed to health warnings of their allocated format only. In the primed decision stage participants will be shown the remaining half of the snack food items and again asked to indicate which foods they would like to consume at the end of the experiment. A measure of dietary self-control will be calculated based on the proportion of healthy but not tasty items chosen for consumption and the number of unhealthy yet tasty items rejected. Participants will be granted one of their chosen items to eat and will be asked to complete demographic and dietary behaviour questionnaires at the end of the experiment.
Interventions
The intervention entails presentation with obesity-prevention health warnings designed to be used in health promotion campaigns at point-of-sale or on food product packaging. Ten health warning messages (derived from the NHMRC Dietary Guidelines for Australians, 2013) were used to create 40 health warnings across four health warning design groups (text-based or text-and-graphic health warnings presented with positive or negative message framing), by altering the message framing and image content
The intervention entails presentation with obesity-prevention health warnings designed to be used in health promotion campaigns at point-of-sale or on food product packaging. Ten health warning messages (derived from the NHMRC Dietary Guidelines for Australians, 2013) were used to create 40 health warnings across four health warning design groups (text-based or text-and-graphic health warnings presented with positive or negative message framing), by altering the message framing and image content of the warnings. An example of a negatively framed health warning message is “Being overweight increases your risk of heart disease.” The positively framed variant of this message reads, “Maintaining a healthy weight reduces your risk of heart disease.” Similarly, the negative graphic variant of this message features an image of an unhealthy heart affected by heart disease, while the positive graphic variant features a stylised ‘healthy’ heart arranged out of fruit and vegetable products. The intervention is delivered at the midpoint (see below) of a single testing session conducted at The University of Melbourne's decision neuroscience laboratory. All participants complete an unprimed/baseline test phase in which they make dietary choices prior to exposure to health warnings. Following this phase, all participants are instructed to attend to and read 10 health warning messages/images (each participants is presented with 10 health warnings of a single health warning format, e.g. participants in the positively framed, text warning group see only positively framed, text-based warnings; text based health warnings were 500 x 300 pixels; graphic health warnings were 500 x 500 pixels) presented centrally on a computer monitor for 8 seconds each (with a 2 - 6 second break between each presentation). During the intervention presentation phase of the experiment, participants are instructed to press the space bar if the border around the health warning stimulus changes colour (which occurs on a random 3 trials out of the total 10), to ensure that participants attend to the health warning messages. Following delivery of the intervention, participants complete a primed/test phase of the same dietary choice task. Participants are allowed to take a self-paced break between the baseline phase, the intervention delivery, and then the test phase. The baseline and test phases are approximately 40 minutes long, while the intervention presentation phase lasts approximately 8 minutes.
Sponsors
Daniel Rosenblatt
Study design
Allocation
Randomised controlled trial
Intervention model
Other
Primary purpose
Prevention
Masking
Blinded (masking used) (Subject)
Eligibility
Sex/Gender
All
Age
18 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
- Men and women aged 18-70 years. - Right-handed. - Familiar with common Australian supermarket snack food brands. - Fluent in spoken and written English.
Exclusion criteria
Subjects will be excluded if they: - Are currently restricting their diet. - Have any medical, ethical, religious or other belief or condition (e.g. coeliac disease, diabetes or following a vegan diet) limiting the consumption of common snack food brands. - Have a past or current eating disorder diagnosis. - Have any food allergies. - Are pregnant.
Outcome results
None listed