The Supplemental Nutrition Assistance Program (SNAP) helps over 37 million Americans meet their food needs. Beginning in 2025, the US Department of Agriculture (USDA) granted states waivers allowing new restrictions on foods purchasable with SNAP. As of this writing, 23 states had been granted waivers. Implementation of restrictions began in some states in January 2026, although their legality has been hotly contested and stopped in some states. Waivers are approved for two years, after which USDA will decide if food restrictions should be extended, with or without evidence to guide that decision. This opinion article examines the methodological and data challenges that threaten efforts to evaluate the effects of SNAP food restrictions, which include variation in state-specific restrictions, inadequate data sources, limitations of nonexperimental study designs, and concurrent changes to SNAP eligibility and participation.