The Impact of a Nutrition Information Program on Food Purchases

A quasi-experimental repeated measures design using a matched set of 20 test and comparison supermarkets in the Washington, D. C. and Baltimore, Md., metropolitan areas was used to evaluate a nutrition information program called "Special Diet Alert" (SDA) introduced by Giant Food, Inc. into Washington, D. C. stores in March 1981. The objective of the SDA program was to help supermarket shoppers find products for special diet needs by providing brand-specific (i.e., individual product level) shelf markers that identified products considered low or reduced in sodium, calories, cholesterol, and fat, supplemented by take-away information booklets available from a rack in the store which listed SDA brand names and specific nutrient values. Market shares of these products were tracked over the two-year evaluation period in Washington, D. C. and Baltimore stores. The pattern of differential sales trends across 16 individual food categories was complicated, but sales of shelf-marked products increased on the average 4 to 8 percent more over the two-year evaluation period in Washington, D. C. than in Baltimore, Md. stores. The average magnitude of effect attributable to SDA was modest in comparison with other factors influencing consumer purchases, highlighting the need for powerful evaluation designs to assess the effectiveness of information programs that operate in the context of many other more powerful influences. Further research is needed to determine which aspects of the SDA program were critical to its success, but one obvious difference between SDA and other in-store nutrition information programs that have been reported in the literature was the use of individual brand-specific shelf markers to deliver nutrition information to shoppers rather than prominently displayed sectional posters and detailed educational pamphlets.