Optimizing an mHealth Intervention to Change Food Purchasing Behaviors for Cancer Prevention

Dietary intake is a powerful, modifiable factor that influences cancer risk. Unfortunately, most adults in the U.S. find it difficult to adhere to dietary guidelines for cancer prevention. One promising pathway for improving dietary adherence is to target grocery shopping habits, i.e., foods purchased for consumption at home. Two-thirds of daily food intake is sourced from or eaten in the home, so improving the quality of the home food environment should improve overall diet quality. When healthy foods are purchased and unhealthy foods are not, minimal self-control is needed to make healthy eating choices in the home. At the point of purchase, it is difficult to resist the temptation of palatable foods, but interventions might facilitate healthy choices by promoting dietary goal salience in real-time while grocery shopping, enhancing motivation to make and sustain changes to the diet, and increasing household support and accountability for healthy food purchasing. The proposed study will enroll adults who have low adherence to cancer prevention dietary recommendations. All participants will attend a nutrition education workshop conducted via Zoom. For 20 weeks, all participants also will receive once weekly reminders and recommendations for food purchasing via an app. The study will experimentally test four additional intervention components: location-triggered messages, coaching monitoring of food purchases, benefit of change content, and household member involvement. The preliminary aim of the study is to assess feasibility and acceptability of the intervention components. The primary aim of the study is to quantify the effect of each intervention component, individually and in combination, on dietary intake (assessed with 24-hour food recalls). The overarching goal of this project is to optimize this mHealth intervention, which can be tested in the future in a fully powered clinical trial.


Eligibility Criteria:
Inclusion criteria

* 18 years or older
* Fluent in English
* Low adherence to cancer prevention dietary guidelines, operationalized as a score of ≤ 2 out of 4 using the National Cancer Institute method for assessing adherence to World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) lifestyle recommendations. This three-level scoring system (meeting/partially meeting/not meeting each recommendation) includes 4 items specific to diet. Participants must score equal or less than 2, meaning that they are fully meeting recommendations for no more than 2 of the 4 dietary recommendations.
* Performs the majority of the household's food shopping, and do so at stores that can passively stream item-level data from a store loyalty card to the Information Machine API (e.g., Walmart, Target, ShopRite, Wegman's, etc.)
* Has a smartphone with iOS or Android operating system that is compatible with the program app
* Lives in a household with at least one other adult who consents to being randomized to possibly receive messages on his/her own cell phone through the program app

Exclusion criteria

* Medical condition or psychiatric condition (e.g., active substance abuse, eating disorder) that may limit appropriateness of or ability to comply with program dietary recommendations
* Planning to enroll in another lifestyle modification program in the next 6 months
* Bariatric surgery history
* Currently pregnant or breastfeeding or planning to become pregnant in the next 6 months