BackgroundThe Supplemental Nutrition Assistance Program (SNAP) is the largest federal nutrition assistance program in the United States, and, accordingly, there is considerable interest in participants' diets. To date, research on SNAP households' dietary behaviors has largely relied on survey‐based dietary assessment methods such as 24‐hour recalls. Electronic household purchase data can provide an important complement to survey‐based measures of SNAP participants' dietary behaviors, as these datasets capture precisely the purchases subsidized by SNAP benefits: i.e., store purchases of foods and beverages for consumption at home. Additionally, a number of jurisdictions have proposed changes to the SNAP benefits package, including ending subsidies for certain items (e.g., sugar‐sweetened beverages [SSBs], junk foods). The scope for these policies to meaningfully change overall dietary quality is bounded by baseline purchases of the targeted products; however, little is known about purchases of policy‐relevant items.ObjectiveThis study aims to describe SNAP households' purchases of key health‐ and policy‐relevant food, beverage, and nutrient outcomes, and to compare these behaviors to those of non‐SNAP households.MethodsData are from a unique dataset of U.S. households' (n = 70,447) packaged food and beverage purchases and SNAP status (current participant, income‐eligible nonparticipant (income ≤130% Federal Poverty Level [FPL]), and higher‐income nonparticipant (>130% FPL)) over three quarters in 2012–2013. We estimated pooled ordinary least squares models, clustered at the household‐level and controlling for sociodemographics, to examine the association between SNAP status and household purchases of 22 nutritional outcomes (e.g., fruits, vegetables, processed meats, SSBs, fiber, calories).ResultsWithin all categories of SNAP status, average household purchases did not meet dietary guidelines for fruits, vegetables, saturated fat, fiber, or sodium. Adjusting for multiple comparisons, we found significant differences by SNAP status in purchases of fruits, salty snacks, processed meat, sweeteners and toppings, SSBs, and total calories, fiber, sugar, and sodium, with all but one comparison (salty snacks) favoring nonparticipant households in terms of healthfulness. Several differences were clinically meaningful: for example, compared to both groups of nonparticipants, SNAP participants purchased approximately 15–20 kcal/person/day more calories from SSBs (p's < 0.0001), approximately 60 kcal/person/day more total calories (p's < 0.0002), and approximately 180–213 more mg/person/day total sodium (p's <0.0002). SNAP households also purchased an average of 565 kcal/person/day from SSBs and junk food, items targeted by SNAP reform proposals. Results were highly robust to corrections for sample selection bias and to exclusion of observations with potentially misreported SNAP status.ConclusionsEfforts to improve dietary quality of SNAP participants may wish to focus specifically on areas where SNAP participants are falling furthest behind nonparticipants and dietary guidelines, such as fruits, sodium, and SSBs. Because baseline purchases of SSBs and junk foods are high, policies to end subsidies for these items could meaningfully reduce total calories purchased, even if these policies are only modestly effective.Support or Funding InformationFunding for this work came from the Robert Wood Johnson Foundation (Grant 67506, 68793, 70017, 71837); NIH (R01DK098072); and the Carolina Population Center (R24 HD050924, T32 HD007168).