Banning the purchase of sugar-sweetened drinks with food stamps could reduce obesity rates and new cases of type-2 diabetes, according to a new study by researchers at the Stanford University School of Medicine.
The food stamp program, officially known as the Supplemental Nutrition Assistance Program, is under pressure from medical groups and nutrition experts to ban the use of its credits to purchase sugary beverages, such as soda and energy drinks. But the beverage industry fights such restrictions to the program, which in 2013 served 20 percent of American households—the highest percentage since the program began in 1969.
Sanjay Basu, MD, PhD, assistant professor of medicine at the Stanford Prevention Research Center, and his colleagues used computerized simulations to estimate the ban's effect. "Restricting or removing the subsidy that SNAP provides for sugar-sweetened beverages would be very likely to reduce type-2 diabetes and obesity among low-income Americans," said Basu, the lead author of the study.
The study was published in the June issue of Health Affairs. Jay Bhattacharya, an associate professor of medicine and an economist at Stanford's Center for Health Policy, was the senior author.
The researchers also simulated giving a 30-cent reward to food stamp participants for each dollar they spent on fruits and vegetables. The simulation's estimates matched the results of the U.S. Department of Agriculture's Healthy Incentives pilot study, which was conducted in a single county in Massachusetts. The reward program would be expected to double the number of people who met the daily recommendation for servings of fruits and vegetables. The simulation allowed the researchers to check their model against real results, and to predict the effects of the Healthy Incentives program nationwide.
"This is a rigorous and well-conducted study," said David Stuckler, PhD, a senior research leader in sociology at Oxford University, in an email. "It reminds us of the critical importance of addressing the root financial causes of rising obesity and diabetes in the United States." (Stuckler, who studies social and economic determinants of health, was not involved in the research.)
But because these findings challenge the subsidies received by the processed-food industry, they are likely to be challenged by lobbying groups, he cautioned.
Other government assistance programs, such as the Special Supplemental Nutrition Program for Women, Infants and Children, do not allow the purchase of sugary drinks and limit purchases to only healthy foods, such as fruits, vegetables, dairy products and whole-grain items. SNAP restricts only the purchase of alcohol, tobacco and hot foods prepared in the store. Soda, salty snacks and junk food are all eligible for SNAP benefits.
Because tax dollars fund SNAP, some groups are concerned that taxpayers are subsidizing an unhealthy diet that will result in more spending on the health-care costs associated with diabetes and heart disease down the road. These costs will largely be borne by Medicare in older individuals and Medicaid in low-income Americans.
In June 2013, a bipartisan group of 18 mayors of major U.S. cities signed a letter addressed to U.S. House Speaker John Boehner and House Minority Leader Nancy Pelosi asking them to add to the 2014 Farm Bill a provision banning the use of SNAP funds for sugar-sweetened beverages. However, these changes were not included in the bill.
Nutrition researchers are paying special attention to sugary drinks because of the way that liquid calories affect the body. They spike sugar levels in the blood and damage the body's ability to respond to insulin and control blood sugar. "Sweetened beverages are off the charts in terms of the diabetes risk they pose," Basu said.
No nutritional value
Also, unlike some other types of junk food (like chips and cookies) that provide small amounts of nutrients, soda has no nutritional value.
To see if restrictions on sugary drinks and a 30-cent refund on fruits and vegetables could improve the health of SNAP recipients, Basu and his colleagues calculated how these two policy changes, if implemented, would affect SNAP recipients over 10 years. They then calculated the risk of obesity and type-2 diabetes among these SNAP recipients, as well as the estimated servings of fruits and vegetables they would eat.
To create the simulation, they used dietary information that was self-reported by both SNAP recipients and nonrecipients on the National Health and Nutrition Examination Survey, a questionnaire put out by the Centers for Disease Control and Prevention. They linked each person's diet with the local cost of food, and then estimated how their eating habits would change if SNAP benefits would no longer pay for sugar-sweetened beverages. The simulation considered that some people would likely continue to buy sweetened beverages, but with their own money, while others would substitute drinks such as fruit juice, which is also high in sugar.
The simulation found that a ban on sugar-sweetened beverages would result in 1.12 percent fewer adults and 0.41 percent fewer children becoming obese. These numbers represent about 281,000 adults and 141,000 children. Diagnosis of adults with type-2 diabetes would decline by 2.3 percent.
The study was careful to make conservative estimates of the effects of a ban, Basu said, and some researchers think that making sugary drinks ineligible for food stamps would have an even greater improvement in recipients' health.
"I feel this paper even underplays the significant effect of changing the SNAP benefits to ban sugar-sweetened beverages, as this would not affect all participants equally and would truly impact heavy consumers, who tend to be more obese and more likely to be diabetic," said Barry Popkin, PhD, professor of nutrition at the University of North Carolina-Chapel Hill, in an email. (Popkin was not involved in the research.)
Increasing fruit, veggie consumption
When researchers looked only at the effects of the 30-cent reimbursement, they found that it would increase each person's consumption of fruits and vegetables by about a quarter of a cup per day on average. Their findings accurately predicted the real-life changes observed in the Healthy Incentives pilot study. By itself, this change would not reduce rates of obesity or type-2 diabetes, but it would double the number of adults who met the federal guidelines for fruit and vegetable consumption.
"It's really hard to get people to eat their broccoli," Basu said. "You have to make it really cheap, and even then, sometimes people don't know what to do with it."
Price isn't the only factor. A person's cultural background, proximity to a grocery store, ability to cook and access to a kitchen can all affect how many servings of fruits and vegetables a person consumes.
Though the reduction in obesity and type-2 diabetes and increase in fruit and vegetable consumption may seem like small numbers, with 46 million Americans receiving SNAP benefits, they represent hundreds of thousands of individuals, Basu said.
"It's very rare that we can reach that many people with one policy change and just one program," he said.