Food Swaps to Improve the Healthfulness and Reduce the Carbon Footprint of Grocery Purchases
- Conditions
- Food SelectionNutritionFood PreferencesDietary HabitsSustainabilityHealthy Diet
- Registration Number
- NCT06648226
- Lead Sponsor
- Stanford University
- Brief Summary
The study aims to determine whether viewing health or climate labels (or both) and receiving recommendations for healthier or more climate-friendly swaps (or both) in an online grocery store environment improves the healthfulness and reduces the carbon footprint of consumers' food and beverage purchases compared to shopping as usual without swap recommendations. The online store will record participants' food selections. Participants will also be asked to complete survey measures.
- Detailed Description
Participants will complete an online between-subjects randomized experiment. The experiment will involve three study visits.
In the first study visit, participants will complete an online grocery store shopping task without intervention. Participants will be given a budget of $50 and asked to shop as they normally would. The store will record participants' food selections. After completing the shopping task, participants will complete an online survey.
Approximately one week later, participants will complete a second study visit with the same instructions. They will be randomized to 1 of 4 conditions (1) health only, 2) climate only, 3) combined health and climate, 4) control. In the health only condition, participants will view labels with nutrition grades and may be directed to swap their selections for healthier items. In the climate only condition, participants will view labels with climate grades and may be directed to swap their selections for more climate-friendly (lower-carbon-footprint) items. In the combined health and climate condition, participants will view labels with health and climate grades and may be directed to swap their selections for healthier or more climate-friendly items. In the control group, participants will not view any labels or swaps. The store will record participants' selections. After completing the shopping task, participants will complete an online survey.
In the third study visit, the participants will maintain their assigned group and will be asked to repeat the same tasks as in the second visit.
Recruitment & Eligibility
- Status
- ENROLLING_BY_INVITATION
- Sex
- All
- Target Recruitment
- 1200
- Aged 18 years or older
- Reside in the United States
- Able to complete a survey in English
- Have internet access to complete the 3 online study visits
- Under the age of 18
- Reside outside of the United States
- Unable to complete a survey in English
- Do not have internet access to complete the 3 online study visits
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Primary Outcome Measures
Name Time Method Healthfulness of product selection Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will asses healthfulness of participants' selections as the average Ofcom Nutrient Profiling Model score of the products the participants select in the shopping task. The score ranges from 0 to 100, where higher scores are healthier.
Carbon footprint of participants' grocery store selections Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess the carbon footprint of participants' selections, operationalized as the average carbon footprint (in CO2-equivalents) of the products the participants select in the shopping task.
- Secondary Outcome Measures
Name Time Method Saturated fat density of participants' grocery selections Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess the average saturated fat density of participants' grocery selections, calculated as the average grams of saturated fat per 100g of the selected products. Higher values will indicate higher saturated fat density.
Fiber density of participants' grocery selections Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess the average fiber density of participants' grocery selections, calculated as the average grams of fiber per 100g of the selected products. Higher values will indicate higher fiber density.
Protein density of participants' grocery selections Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess the average protein density of participants' grocery selections, calculated as the average grams of protein per 100g of the selected products. Higher values will indicate higher protein density.
Total spending on participants' grocery selections Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess the total amount participants spent on their grocery selections in United States dollars. Higher values will indicate greater spending.
Calorie density of participants' grocery selections Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess the average calorie density of participants' grocery selections, calculated as the average kcal per 100g of the selected products. Higher values will indicate higher calorie density.
Sugar density of participants' grocery selections Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess the average sugar density of participants' grocery selections, calculated as the average grams of sugar per 100g of the selected products. Higher values will indicate higher sugar density.
Sodium density of participants' grocery selections Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess the average sodium density of participants' grocery selections, calculated as the average milligrams of sodium per 100g of the selected products. Higher values will indicate higher sodium density.
Thinking about health Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess thinking about health using 1 item: "We are interested in how you selected products while you were grocery shopping. When you selected foods, how much did you think about each of the following characteristics? ... health." Response options range from "Not at all" (1) to "A great deal" (5).
Thinking about climate impact Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess thinking about climate impact using 1 item: "We are interested in how you selected products while you were grocery shopping. When you selected foods, how much did you think about each of the following characteristics? ... climate impact." Response options range from "Not at all" (1) to "A great deal" (5).
Thinking about taste Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess thinking about taste using 1 item: "We are interested in how you selected products while you were grocery shopping. When you selected foods, how much did you think about each of the following characteristics? ... taste." Response options range from "Not at all" (1) to "A great deal" (5).
Injunctive norms to buy foods with low climate impact Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess injunctive norms to buy foods with low climate impact with 1 item: "People who are important to me think I should buy foods with low climate impact." Response options range from "Strongly disagree" (1) to "Strongly agree" (5).
Descriptive norms to buy foods with low climate impact Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess descriptive norms to buy foods with lower climate impact with 1 item: "Most shoppers buy foods with low climate impact when they are shopping for groceries." Response options range from "Strongly disagree" (1) to "Strongly agree" (5).
Descriptive norms to buy healthy foods Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess descriptive norms to buy healthy foods with 1 item: "Most shoppers buy healthy foods when they are shopping for groceries." Response options range from "Strongly disagree" (1) to "Strongly agree" (5).
Injunctive norms to buy healthy foods Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess injunctive norms to buy healthy foods with 1 item: "People who are important to me think I should buy healthy foods." Response options range from "Strongly disagree" (1) to "Strongly agree" (5).
Negative emotional reactions while shopping Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess negative emotional reactions using 3 items: "While you were shopping, how much did you feel..." "worried", "guilty," "ashamed"? Response options range from "Not at all" (1) to "Extremely" (5). The investigators will average the 3 items; higher average scores indicate stronger negative emotional reactions.
Positive emotional reactions while shopping Assessed at baseline, 1-week follow-up, and 2-week follow-up The study will assess positive emotional reactions using 3 items: "While you were shopping, how much did you feel..." "inspired", "proud," "reassured"? Response options range from "Not at all" (1) to "Extremely" (5). The investigators will average the 3 items; higher average scores indicate stronger positive emotional reactions.
Trial Locations
- Locations (1)
Stanford School of Medicine
🇺🇸Palo Alto, California, United States