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

Study Summary

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.

Primary Outcome

In Wave 1, the primary outcome will be change from 0-20 weeks in dietary intake of the major food categories from the American Institute for Cancer Research guidelines. Self-reported dietary recalls will be completed for three days at baseline and week 20 using the Automated Self Administered 24-hour food recall (ASA-24). This table reports the change in grams of fiber per day. This pilot study used a factorial design, with 16 conditions and typically 4 participants per condition. The study was

Interventions

• BEHAVIORAL Location-triggered notification
• BEHAVIORAL Reflections on benefits of change
• BEHAVIORAL Coach monitoring
• BEHAVIORAL Household support