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Alan Mathios poses at Wegman's in the salad dressing aisle; his study of salad dressings found that when mandatory labeling was instituted, the sales of high-fat dressings declined, suggesting that food labels may influence consumer choices.

After more than six years of mandatory food labeling, consumers are becoming savvier about high-fat foods on grocery shelves, says a Cornell University economist. In a study, he found that sales of high-fat dressings significantly declined after mandatory labeling was instituted, providing evidence that the labels are influencing the sales of other high-fat foods as well.

To study how nutrition labels affect consumer choices, Alan D. Mathios, associate professor of policy analysis and management at Cornell, conducted a study of supermarket data of salad dressings purchased before and after the Nutrition Labeling and Education Act (NLEA) mandatory labeling law went into effect in 1994. Prior to the label law, all low-fat salad dressings carried nutrition labels, says Mathios, but the vast majority of high-fat dressings didn't.

"We chose to study salad dressings because they were relatively easily to analyze," says Mathios. "The study provides powerful evidence that mandatory nutrition labeling can effectively change consumer choices, suggesting that it may influence purchases of other high-fat foods as well."

By studying the bar-code data from supermarket scanners, he found that before the nutrition labeling law, the high fat, unlabeled salad dressings accounted for almost 75 percent of all salad dressings purchased by the least educated shoppers and almost 50 percent of the salad dressings bought by the most educated shoppers. (Supermarket shopper-club applications provided the demographic data.) Once the high-fat dressings were required to carry labels indicating their fat content, their sales declined about 5 percent.

Mathios' findings were published in a recent issue of the Journal of Law & Economics (Vol. XLIII, No. 2, October 2000).

Salad dressings vary widely in their amount of fat per serving, ranging from zero grams to up to 20 grams of fat per serving (that's almost one-third the recommended daily intake of fat for a middle-aged, average-sized woman). "These findings are important because the impact of mandatory nutrition laws on dietary choices has significant policy implications, since five of the top 10 leading causes of death in the United States are related to diet," said Mathios.

Mathios collected supermarket scanner data at 20 Wegman's supermarkets before and after mandatory labeling, during identical weeks of the year with almost the identical set of products.

The Cornell economist studies the effect of information-dissemination policies and regulations on consumer welfare and the roles of advertising, labeling and marketing in food and nutrition policy.

The study was supported by a U.S. Department of Agriculture Hatch grant.