CHAPEL HILL, N.C.—A new University of North Carolina at Chapel Hill study revealed a direct correlation between fast-food pricing and weight and risk for diabetes. The study, published in the Archives of Internal Medicine, found weight and diabetes risk decreased for people in communities where fast-food prices increased. Conversely, when fast-food prices fell, then consumption, weight and diabetes risks rose.
Researchers used data from more than 5,000 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study. When it started in 1985, CARDIA participants lived in four U.S. cities. In the intervening years, participants have moved to 48 states. Researchers collected information on the average prices of products, including restaurant pizza, burgers, soft drinks and whole milk in the counties in which each participant lived. Prices were adjusted to 2006 levels.
When researchers analyzed the diet, weight and insulin levels of study participants, they found that when prices of fast foods and sodas went up just 10 percent, participants consumed on average 7.1 percent fewer calories from soda and 11.5 percent fewer calories from pizza. That translates to about 56 calories a day less, which corresponds to a reduction of about 3 to 4 pounds a year per person. The participants who found their fast food prices rose also gained less weight and had a lower risk for diabetes based on a test for fasting insulin (HOMA-IR).
“For these fast foods, taxes would represent the most effective way to reduce adult obesity that we have today, based on this research,” the researchers wrote.