A new study shows only one in three adults could correctly calculate the number of carbohydrates in a bottle of soda containing 2½ servings using the information printed on the food label.
Only 60 percent could calculate the number of carbohydrates they'd consume if they ate half a bagel when the serving size was a whole bagel.
"The study showed that many patients struggle to understand current food labels, and that this can be particularly challenging for patients with poor literacy and numeracy (math) skills," says researcher Russell L. Rothman, M.D., MPP, in a news release. "Poor understanding of nutrition labels can make it difficult for patients to follow a good diet," says Rothman, who works at Vanderbilt University.
In the study, researchers surveyed 200 adults from a variety of socioeconomic backgrounds who visited a primary care clinic. Participants completed math and reading skills tests as well as a nutritional label survey designed to evaluate their understanding of food labels.
Nearly 70 percent of those surveyed had at least some college education and 77 percent had at least ninth-grade level literacy. However, the study showed most — 63 percent — had less than ninth-grade level math skills.
Overall, the participants correctly answered 69 percent of the questions on the nutritional label survey.
Most said they found food labels easy to understand, but the results showed even those with high literacy skills had difficulty applying the nutritional information found on the labels.
The most common mistakes involved interpretation and application of serving size, confusion over labeling information, and calculation error.
In addition, the researchers say many of the newer low-carbohydrate products were particularly difficult for people to understand, especially when the net carbs information was printed outside the nutritional facts panel.
Researchers say the results are particularly concerning because more than 40 percent of those surveyed had a chronic illness, such as diabetes or high blood pressure, for which following a specialized diet is important. In fact, nearly a quarter of the participants said they were on a specific diet plan.
The results appear in the American Journal of Preventive Medicine.
SOURCES: Rothman, R. American Journal of Preventive Medicine, November 2006; Vol. 31. News release, American Journal of Preventive Medicine.
By Jennifer Warner
Reviewed by Louise Chang, M.D