Study: NYC-Style Cap on Soda Size Would Target the Overweight, Not the Poor

13 June 2013 --- Legislation to restrict consumption of large sugar-sweetened beverages in food service establishments would affect 7.5% of Americans on a given day, and a greater percentage among those who are overweight, including 13.6% of overweight teenagers, according to researchers at Columbia University's Mailman School of Public Health.

Challenging criticism that the restriction is discriminatory against the poor, the study finds low-income individuals would not be disproportionately affected.

The proposed restrictions were approved by the New York City Board of Health. They are currently under appeal after being struck down by the New York State Supreme Court in March. Oral arguments began yesterday.

The new study looks at national data, but the researchers say the results are a strong validation of the obesity-prevention measure no matter where in the country it is implemented. "Our findings are clear: a law like this would address one of the fundamental causes of obesity—the growing portion size of sweetened drinks," says lead author Y. Claire Wang, MD, ScD and assistant professor of Health Policy and Management at Columbia University's Mailman School of Public Health. The study appears online in the American Journal of Clinical Nutrition.

Dr. Wang and co-author Seanna M. Vine, MPH, analyzed 19,147 dietary records from National Health and Nutrition Examination Surveys in the years 2007-2010 for the demographics related to the consumption of sugar-sweetened beverages, including sodas and other non-alcoholic drinks containing caloric sweeteners.

While 60.5% of Americans consumed sugary drinks on a daily basis, only 7.5% purchased them from a food establishment in portions larger than 16 ounces on a given day. The proportion was marginally higher in some groups: 8.6% of those who were overweight (compared to 6.4% of those who aren't overweight), 13.6% of overweight teenagers, and 12.6% of overweight young adults aged 20 to 44. Americans with incomes less than 130% of the poverty line (eligible for the Supplemental Nutrition Assistance Program, SNAP, formerly food stamps) were found to consume large sugary drinks from food service establishments in equal proportion to those with higher incomes.

The results are surprising given that low-income Americans are more likely to consume sugary beverages in a given day than higher-income groups. The difference could be that fewer of these beverages are being purchased in restaurants. "Buying a large soda and drinking it at home costs less," says Dr. Wang.

Until the legislation is enacted, it is impossible to know to what extent the consumption of sugary beverages will change. Under the proposed policy, consumers would be free to drink as much as they would like, and restaurants could offer free refills or discounts on multiple servings. Given these uncertainties, the researchers used a variety of scenarios to estimate how the policy would cut calories and consumption. A reasonable assumption, they say, would be that 80% of large soda drinkers downsize to a 16-ounce soda and 20% splurge on two 16-ounce sodas. In this case, adults would cut 63 calories daily; children and teenagers affected by the policy would cut 58 calories. Both would avoid three to four teaspoons of sugar.

These calorie reductions could go a long way toward reducing the number of excess calories taken in by American youth. Previous research by Dr. Wang found that a reduction of 64 calories per day is needed to reach the country's Healthy People 2020 goal for reducing obesity.

The researchers also looked at where people consumed large sweetened drinks outside the home. Among food service establishments, 65% of the drinks were consumed in fast food restaurants, followed by 28% in restaurants with wait staff; 4% in a sports stadium, movie theater, or other entertainment venue; 2% from a street vendor; and 1% from a bar. These numbers would be slightly different in New York City, notes Dr. Wang, where there are more street vendors and full-service restaurants than the rest of the country.

The portion size cap might also have a spillover effect, influencing behaviors in the home, where most sugary drinks are consumed, says Dr. Wang, who co-leads a Dean's Initiative at the Mailman School focused on advancing research on preventing obesity. "Changing social norms is difficult, but as portion sizes have grown, it's useful to establish a new standard."

When first introduced in 1955, a regular-size soda at McDonald's was 7 ounces. Today the chain offers 12-ounce drinks as the child size, 16-ounce drinks as small, 21-ounce drinks as medium, and 32-ounce drinks as large. In 1999-2004, an average U.S. teen consumed 301 calories in sugar-sweetened beverages, which is 13% of their total daily calories. To burn this off, they would need to walk more than 5 miles.

"This is an important study. It provides critical foundational evidence that the proposed efforts to restrict marketing of large sodas in New York City and elsewhere can have a substantial impact on population health," says Sandro Galea, MD, DrPH, chairman of the department of Epidemiology at the Mailman School and a member of the New York City Board of Health.