A Call for New Research in the Area of Nutritional Standards in SNAP

The Supplemental Nutrition Assistance Program (SNAP) provides benefits that help eligible low-income households purchase food. Most enrolled households supplement SNAP benefits with personal funds (Tiehen, Newman, and Kirlin 2017). The Congressional Budget Office estimates that in 2025, an average of 42.5 million people will receive SNAP benefits each month, with an average monthly benefit of $188 per recipient (CBO 2025).

SNAP benefits can be used to buy many foods, although some items, such as hot prepared meals, are excluded. Lawmakers have asked CBO how adding nutritional standards to SNAP might affect the federal budget. Such standards would restrict purchases of foods linked to poor health outcomes, such as sugar-sweetened beverages, using SNAP benefits. New research would help the agency assess their budgetary effects.

How Would Nutritional Standards in SNAP Affect the Federal Budget?

To assess the budgetary effects of adding nutritional standards to SNAP, CBO would estimate:

• The costs of implementing the policy,
• Any offsetting savings resulting from the improved health of SNAP recipients, and
• Any savings from reduced participation in the program.

Estimating savings from improved health requires evidence about changes in food purchases and consumption and how those changes affect diet quality, health outcomes, and spending on health care. The federal budgetary effects would depend on SNAP recipients' health insurance coverage and federal subsidies for that coverage. Although CBO's cost estimates focus on a 10-year period, the agency would, if practicable, assess longer-term budgetary effects.

To gather that evidence, the agency examined two main types of research: randomized controlled trials (RCTs) and simulation models specific to the SNAP population. In CBO's assessment, that research literature has limitations stemming from the relatively small number of existing studies and from differences in conclusions among studies that have used different methodological approaches.

CBO also reviewed the literature on how taxes on sugar-sweetened beverages affect food consumption, health, and health care spending. If restrictions on SNAP purchases effectively raise the prices of targeted items, people may respond much as they do to those taxes. Although other interventions also aim to reduce the consumption of unhealthy foods, CBO focused on sugar-sweetened beverage taxes because of the strength and depth of the evidence in that area.

What Have RCTs Found About the Effects of Nutritional Standards in SNAP or Similar Programs on Diet Quality?

In CBO's assessment, the evidence on how SNAP beneficiaries would respond to restrictions on items that are eligible for purchase with SNAP benefits is unclear. Two RCTs found that restrictions on sugary foods alone did not improve the diets of low-income households receiving SNAP-like benefits (Harnack and others 2024; Harnack and others 2016). The lack of an effect may have been due to recipients' use of their own funds to buy restricted items or their substitution of similar foods.

Those studies also examined the combined effects of restrictions and incentives (that is, additional funds for the purchase of healthier foods), with mixed results. The 2016 study showed improved diet quality, but the 2024 study found no improvement. Methodological differences could explain those inconsistent findings.

Direct evidence that incentives can improve food consumption among SNAP recipients has come from the Healthy Incentives Pilot, a 2011 RCT involving a large group of SNAP recipients. In that study, participants who received an additional 30 cents for every SNAP dollar spent on certain fruits and vegetables consumed about 25 percent more of those items daily than participants who received standard SNAP benefits (Bartlett and others 2014).

What Do Simulation Models Suggest About the Effects of Nutritional Standards in SNAP on Health and Health Care Spending?

Diet quality can affect health. For certain populations, such as people with diet-related chronic diseases, dietary improvements can have clear benefits in the near term (see, for example, Estruch and others 2018; Appel and others 1997). For other populations, such as children, some evidence suggests that improvements in diet quality, including lower exposure to sugar, can improve health over the longer term (Gracner, Boone, and Gertler 2024; Gertler and Gracner 2022).

Three simulation studies have estimated how nutritional restrictions in SNAP would affect health and health care spending (Choi, Wright, and Bleich 2021; Mozaffarian and others 2018; Basu and others 2014). Those studies modeled how SNAP recipients would change their consumption behavior in response to changes in program rules, accounting for the fact that recipients often shift some spending between SNAP benefits and personal funds when SNAP policies change. The studies linked the projected changes in consumption to expected health outcomes and health care costs, using evidence from prior research.

Findings from those simulation studies suggest that restricting purchases of sugar-sweetened beverages with SNAP dollars would improve health outcomes. One study found that restrictions would lead to lower obesity rates and lower incidence of type 2 diabetes (Basu and others 2014). Another suggested that restrictions would reduce cases of cardiovascular disease and health care spending (Mozaffarian and others 2018). The third study found that restricting purchases of sugar-sweetened beverages would reduce dental cavities among children, but the effects on obesity would vary depending on food substitutions (Choi, Wright, and Bleich 2021).

Two of those three studies also modeled the effects of incentives alone, with mixed results: One found that incentives on their own would not change health outcomes (Basu and others 2014), whereas the other found that incentives would lead to improvements in health and reductions in health care spending (Mozaffarian and others 2018).

What Have Research Studies Found About the Effects of Sugar-Sweetened Beverage Taxes on Health?

Eight cities or areas in the United States have imposed taxes on sugar-sweetened beverages (World Bank 2023). There is substantial evidence showing that taxes reduce sales of such beverages but limited evidence linking those reductions in sales to improvements in health (Hoffer and Macumber-Rosin 2025; Cawley and Frisvold 2023). Improvements in health may be limited because people substitute the taxed beverages with other high-calorie products or travel to areas without such taxes to purchase them (Hoffer and Macumber-Rosin 2025; Cawley and others 2019).

SNAP participants may respond to restrictions on unhealthy food purchases similarly to how consumers react to sugar-sweetened beverage taxes—by reducing consumption—if they perceive those restrictions as price increases. That perception depends on whether participants view SNAP benefits as equivalent to cash. If they do, they may simply use cash to buy restricted items. But people often treat SNAP benefits and cash differently (Hastings and Shapiro 2018). In that case, restrictions may effectively raise the perceived cost of targeted products, decreasing their consumption.

What New Research Would Be Especially Useful?

Additional research on how nutritional standards affect SNAP recipients' food choices, health outcomes, and health care spending would help CBO provide more complete information to the Congress. Key areas that would benefit the agency's analysis include the effects of the consumption of specific foods on overall diet quality; the extent to which changes in diet alone affect health, when many factors influence health; differences in policy effects among subgroups of people (based on age or prevalence of chronic conditions); and the near- and long-term implications of nutritional standards for health and health care spending. Research on how SNAP enrollment changes in response to nutritional standards is also needed. Restrictions could make the program less desirable, potentially reducing enrollment. Evidence on such changes in enrollment would help CBO estimate the effects on the program's costs. And additional evidence on how participants substitute between SNAP benefits and cash would further inform the agency's projections of the likely effects of nutritional standards in the program.

Different study designs could help fill those gaps:

• New RCTs would be valuable. Ideally, studies would randomly assign SNAP benefits with and without nutritional standards to large numbers of recipients across geographic areas, track purchases of food with SNAP benefits and with personal funds, and collect information on consumption. Linking that information to health metrics, health care spending, disability claims, and employment records would allow CBO to examine a wide range of near- and long-term outcomes.
• Studies using simulation models could illustrate the sensitivity of results to different inputs and assumptions. CBO would also benefit from reviewing the code underlying those models.
• Natural experiments, in which policy changes subject some people to an intervention but not others, would also be useful. Those studies would compare outcomes in areas where nutritional standards are adopted with outcomes in similar areas where they are not adopted.

Because each design has strengths and limitations, those different designs are complementary. For example, RCTs are considered ideal for isolating the effects of an intervention, but their relevance can be limited by small sample sizes, short time frames, and high attrition rates. Simulation models can use survey data to assess larger samples over longer time frames, but they require simplification of complex behavioral and physiological mechanisms and are dependent on the quality of inputs and assumptions. A mix of designs would therefore strengthen the evidence base.

Noelia Duchovny is an analyst in CBO's Health Analysis Division. This blog post includes contributions from the following CBO staff: Susan Yeh Beyer, Elizabeth Cove Delisle, Jennifer Gray, Tamara Hayford, Rebecca Heller, Jeffrey Kling, Aditi Sen, Emily Stern, Julie Topoleski, Chapin White, and Heidi Williams (a consultant to CBO).

As part of the legislative process, CBO supplies the Congress with cost estimates for legislation, economic and budget projections, and other economic assessments. Information from the research community is an important element of CBO's analyses. This is the 11th in a series of blog posts discussing research that would enhance the quality of the information that CBO uses in its work. (Earlier posts in the series discussed the need for new research in the areas of energy and the environment, finance, health, hepatitis C, labor, macroeconomics, national security, new drug development, obesity, and taxes and transfers.) Please send comments to communications@cbo.gov.