PROJECT SUMMARY The Administrative Supplement to my Mentored Research Scientist Development Award (K01AG064146) will provide additional support to my long-term career objective of becoming an independent investigator who specializes in improving diet practices and preventing chronic disease development in high-need groups, including those with food insecurity and older immigrant adults. Some choice-based food pantries in the U.S. are transitioning to online ordering. This transition is significant because online ordering may increase the use of food pantries overall and increase food security, potentially via increased self-efficacy and reductions in wait times and stigmatization. In addition, potential improvements in food security may vary by age group, given key differences in barriers to food pantry use among younger versus older food pantry clients. To our knowledge, however, there have been no evaluations of the transition to online ordering in food pantries. Building on the research and training goals of my K01 award, the specific aims of this Administrative Supplement are: 1) Determine whether the transition to online ordering at a choice-based food pantry network in New York City influences food security status among low-income adults using a natural experiment design; and 2) Determine whether there are differences in outcomes by age group. We will accomplish these aims by recruiting 386 low- income adults aged >18 years from Met Council's Kosher Food Network, including 193 clients who visit a food pantry on the cusp of transitioning to their Digital Choice Food Pantry System and 193 clients who visit a client- choice food pantry not transitioning to online ordering (controls). The findings from the proposed research will support the development of a novel approach to improving food security and healthy food choice in a high- need population, while still being within the scope and timeline of the Parent Grant. This supplement will also build on the training plan of the Parent Grant, enabling me to enhance my understanding of: 1) aging and health, 2) behavioral economics, 3) experimental research methods, and 4) survey design; and, uniquely, 5) provide training in community-partnered research methods, which is important for the sustainability and significance of my research agenda. The proposed supplemental aims will also support my transition to scientific independence and, importantly, strengthen my future applications for competitive funding.