The aim of this study is to compare responses to 6 different types of labels for restaurant menus: 1) a QR code on all items (control); 2) High Climate Impact label; 3) High Climate Impact Warning label; 4) Climate Grade label; 5) Climate Grade label also displaying full range of possible grades; 6) Estimated Environmental Cost label. Participants will be randomized to 1 of these 6 labeling arms. Each participant will view a menu based on a real-world restaurant with one of the 6 labels shown on applicable menu items, select the menu item they would like, and then respond to survey questions about each label.
This is an online randomized controlled trial in which researchers will use a survey company to recruit participants to an online survey. In the study, participants will be randomized to 1 of 6 labeling arms: 1) a QR code on all items (control); 2) High Climate Impact label; 3) High Climate Impact Warning label; 4) Climate Grade label; 5) Climate Grade label also displaying full range of possible grades; 6) Estimated Environmental Cost label. Labels will only appear alongside main menu items and will be assigned using thresholds for greenhouse gas emissions set a priori in kilograms of CO2 equivalent per kilogram of food. Each participant will view a menu based on a real-world restaurant with one of the 6 labels shown on applicable menu items, select the menu item they would like, then respond to survey questions about each label. For dichotomous outcomes, the investigators will directly estimate the probability ratio using Poisson regression with a robust error variance, regressing the outcome on indicators for experimental condition. For continuous outcomes, the investigators will use linear regression models, regressing the outcome on indicators for experimental condition. A critical alpha 0.05 will be used, and statistical tests will be two-tailed. Investigators will compare all experimental label conditions to the control label, then compare each experimental label to each other using pairwise comparisons.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Participants will view a sample of items from a restaurant menu, displayed with labels
University of California, Davis
Davis, California, United States
High climate impact menu item selected - dichotomous variable
Measured as a dichotomous variable (yes/no) indicating whether participants' hypothetical meal orders include a high climate impact menu item.
Time frame: Up to approx. 1 minutes
Total greenhouse gas emissions - continuous variable
Cumulative total kilograms of carbon equivalent (kgCO2e) per kilogram of food for all meal items.
Time frame: Up to approx. 1 minute
Modified Nutrient Profile Index (NPI) score - continuous variable
NPI scores are based on the UK Ofcom Nutrient Profiling Model, which is used to score individual foods in the U.K. to determine which ones can be marketed to children. The NPI generates a 0 to100-point score for foods and beverages where scores \>=64 are considered healthy. NPI scores are based on points awarded from nutrients to encourage (e.g., percent fruits and vegetables, grams of fiber and protein) and nutrients of concern (e.g., sodium, sugar) per 100 grams. For this study, we will generate a modified NPI score to evaluate the healthfulness of full meals comprised of multiple food items. This measure will be determined by calculating the weighted mean NPI score of all food items selected per meal, with each item's NPI score weighted by its proportionate contribution of mass in grams to the total mass of the meal. Reference: Rayner, M., Scarborough, P., Boxer, A., \& Stockley, L. (2005). Nutrient profiles: development of final model. London: Food Standards Agency.
Time frame: Up to approx. 1 minute
Total energy (kcal) selected - continuous variable
The total number of calories in participants' hypothetical meal orders, calculated as the sum of calories across all menu items selected. Higher values indicate more calories selected.
Time frame: Up to approx. 1 minute
Total saturated fat (g) selected - continuous variable
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Enrollment
16,181
The total grams of saturated fat in participants' hypothetical meal orders, calculated as the sum of grams of saturated fat across all menu items selected. Higher values indicate more saturated fat selected.
Time frame: Up to approx. 1 minute
Total sodium (mg) selected - continuous variable
The total milligrams of sodium in participants' hypothetical meal orders, calculated as the sum of milligrams of sodium across all menu items selected. Higher values indicate more sodium selected.
Time frame: Up to approx. 1 minute