Diet Habit, Diet Modification
Conditions
Brief summary
The purpose of this study is to test whether individual-level targeted price incentives for healthier foods can improve the diet quality of grocery purchases made by adults in comparison to a one size fits all approach. To test this, the investigators plan to implement a 8-month randomized controlled cross-over trial. The intervention group will receive a small discount for using their loyalty card and weekly coupons for healthier foods (e.g. fruits, vegetables, whole grains, lean meats and seafood, low-fat dairy) that are selected based on the individual's past purchase history, dietary preferences, their baseline diet quality, and their estimated likelihood of using the coupon. Individualized coupons will be automatically sent to customers' loyalty cards each week, and separate emails with appropriate nutrition education and information about the coupons will be sent to participants weekly. The control group will receive a small discount for using their loyalty cards during the first phase of the study (3-months), occasional untargeted coupons, and weekly emails with untargeted nutrition education. Following phase1, there will be a 2-month washout period, and then the intervention and control groups will cross over for the remaining 3-months of the study. The investigators will collect purchase data from all participants as well as food frequency questionnaires and other self-reported behavioral and health questions at baseline, after phase 1 completion, and after phase 2 completion. The investigators hypothesize that participants in the intervention group will meaningfully improve the overall quality of their food purchases (measured using the Grocery Purchase Quality Index-2016) as well as their overall diet quality (measured using the Healthy Eating Index 2010.
Detailed description
A detailed description of Eligibility and outcome measures is entered elsewhere
Interventions
BEHAVIORALTargeted incentives
Participants receiving individually-targeted incentives will receive weekly coupons for healthier foods that are informed by their purchase history, responses to behavioral and health questions, food preferences, and need for improvement in different categories
BEHAVIORALNominal loyalty card discount and nutrition education
All participants will receive a nominal discount on all groceries for using their loyalty card and nutrition education through weekly emails.
Sponsors
University of Rhode Island
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* 18 years or older * Speaks English * Non-store employee * Primary shopper in the household * Purchases at least half of weekly groceries at supermarket * Not pregnant or planning on becoming pregnant before April 2019
Exclusion criteria
* Younger than 18 years of age * Does not speak English * Employee at supermarket * Pregnant or planning to become pregnant before April 2019 * Not primary shopper for household * Purchases less than half of weekly groceries at supermarket
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Likelihood of purchasing targeted products | 3- 6- and 9-month changes within and between the intervention and control groups | Within produce, whole grain cereals & breads, lean meats, low-fat dairy, and beverages, will look at the proportion of expenditures (i.e. percent of dollars) in those categories before and after the intervention between treatment and control group. |
| Grocery Purchase Quality Index (GPQI) 2016 | 3, 6- and 9-month changes in the GPQI-16 and its components within and between the intervention and control groups | The GPQI is a validated measure for scoring the quality of household grocery purchases by comparing the percent spent within different food categories with recommended spending. https://utah.pure.elsevier.com/en/publications/the-grocery-purchase-quality-index-2016-an-innovative-approach-to |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Healthy Eating Index (HEI) -2010 for the primary shopper | 3, 6- and 9-month changes in the HEI-10 and its components within and between the intervention and control groups | The HEI-10 is a validated measure of individual-level diet quality that measures compliance with US Dietary recommendations. https://www.ncbi.nlm.nih.gov/pubmed/24453128 |
| Percent expenditures within targeted categories | 3, 6- and 9-month changes in percent spending in targeted categories within and between the intervention and control groups | The investigators will compute the percent of shopping dollars people spend in fruits, vegetables, whole grains, dairy, lean meat, and seafood. |
| Self-reported height and weight used to compute body mass index (BMI) | 3, 6- and 9-month changes in BMI | The investigators will compute body mass index from self-reported weight in pounds and height in inches (weight (lbs) \* 703/height (in)/height (in) |
Other
| Measure | Time frame | Description |
|---|---|---|
| Self-reported food neophobia as an effect modifier on the primary and secondary outcomes | Baseline and 9-months | The investigators will examine whether food neophobia modifies the effect of the intervention on the primary and secondary outcomes. Food neophobia was measured via 8 self-reported questions with a 5-point Likert scale ranging from completely disagree to completely agree. Responses will be summed, and higher scores reflect greater variety-seeking in eating experiences (i.e. less neophobia). We will test for an interaction between this continuous measure and the intervention on specified primary and secondary outcomes |
| Coupon proneness as an effect modifier on the primary and secondary outcomes | Baseline and 9-months | The investigators will examine whether coupon proneness modifies the effect of the intervention on the primary and secondary outcomes. Coupon proneness was measured via a 22-item self-reported questionnaire with 7-point Likert scales. Higher scores indicate greater likelihood of using coupons. |
| Self-reported food literacy as an effect modifier on the primary and secondary outcomes | Baseline | The investigators will examine whether food literacy modifies the effect of the intervention on the primary and secondary outcomes. Food literacy was measured using a 12-item questionnaire, with 4- and 5-point Likert type scales, with higher scores indicating greater food literacy. |
| Nutritional self-efficacy as a modifier on the primary and secondary outcomes | Baseline | The investigators will examine whether nutritional self-efficacy modifies the effect of the intervention on the primary and secondary outcomes. Nutrition self-efficacy was measured via self-report using a 5-item scale with Likert responses (range 0-3) with higher scores indicating greater self-efficacy in nutritional domains. |
| Food security as a modifier on the primary and secondary outcomes | Baseline and 9-months | The investigators will examine whether food security modifies the effect of the intervention on the primary and secondary outcomes. Household food security was assessed via a 6-item short form, with higher scores indicating greater food insecurity. |
Countries
United States
Outcome results
None listed