Understanding Graduate Students' Perspectives on Food Apps to Inform User-Centered Design: Explanatory Sequential Mixed Methods Survey Study.

Background: Mobile food apps have the potential to promote healthier eating behaviors and more sustainable food practices. Graduate students often struggle to maintain healthy dietary habits due to lifestyle transitions, academic stress, limited time, and constrained budgets, which can lead to poor meal planning, irregular eating patterns, and increased food waste. Objective: This study aimed to examine graduate students' dietary behaviors, food waste practices, and preferences for mobile food app features, with the intention of informing the design of user-centered tools that promote healthy eating and reduce food waste. Methods: This study used an explanatory sequential mixed methods design. In the first phase, 63 graduate students at the University of South Carolina completed an online survey between November and December 2024, which captured demographics, cooking habits, dietary preferences, food waste behaviors, and online recipe search behaviors. Findings from the survey shaped the design of interview questions, allowing qualitative inquiry to explain and expand upon the quantitative patterns. Ten purposively selected participants completed semistructured interviews. Quantitative data were analyzed descriptively and using the chi-square test with R software (version 4.3.1), while qualitative data were transcribed and thematically analyzed. Results: Survey findings revealed that 54% (34/63) of the participants ate out daily or almost daily; 25.3% (16/63) consumed fast, frozen, or canned food at least 3 to 5 times per week; and only 19% (12/63) cooked daily. Most participants consumed only 1 serving of vegetables (43/63, 68.2%) and fruits (33/63, 52.4%) daily. Nearly 70% (44/63) reported food waste, primarily from leftovers and unused ingredients. A significant association was found between shopping list use and reduced food waste (χ²1=9.66, P=.008; Cramér V=0.39). The interviews contextualized these patterns: the students described time constraints, limited cooking skills, and overbuying as key barriers to healthy eating and waste reduction, while recommending app features such as nutrition tracking, batch meal planning, personalized dietary filters, ingredient-based recipe generators, and grocery list tools with reminders. Participants also emphasized the importance of simple design, multimodal content, and accurate cooking time estimates. Conclusions: This study demonstrates that integrating quantitative and qualitative insights through the capability, opportunity, motivation-behavior (COM-B) framework provides a nuanced understanding of graduate students' dietary practices, food waste behaviors, and app feature preferences. The findings highlight the need for mobile food apps that are not only evidence based but also user centered, offering simple, time-efficient, and customizable tools that simultaneously address capability deficits, opportunity barriers, and motivation maintenance. Such apps have the potential to address barriers unique to graduate students, such as limited time, minimal cooking skills, and organizational challenges, while supporting healthier eating and reducing food waste.