Change in trans fatty acid content of fast-food purchases associated with New York City's restaurant regulation: a pre-post study

Abstract

Background: Dietary trans fat increases risk for coronary heart disease. In 2006, New York City (NYC) passed the first regulation in the United States restricting trans fat use in restaurants.

Objective: To assess the effect of the NYC regulation on the trans and saturated fat content of fast-food purchases.

Design: Cross-sectional study that included purchase receipts matched to available nutritional information and brief surveys of adult lunchtime restaurant customers conducted in 2007 and 2009, before and after implementation of the regulation.

Setting: 168 randomly selected NYC restaurant locations of 11 fast-food chains.

Participants: Adult restaurant customers interviewed in 2007 and 2009.

Measurements: Change in mean grams of trans fat, saturated fat, trans plus saturated fat, and trans fat per 1000 kcal per purchase, overall and by chain type.

Results: The final sample included 6969 purchases in 2007 and 7885 purchases in 2009. Overall, mean trans fat per purchase decreased by 2.4 g (95% CI, -2.8 to -2.0 g; P < 0.001), whereas saturated fat showed a slight increase of 0.55 g (CI, 0.1 to 1.0 g; P = 0.011). Mean trans plus saturated fat content decreased by 1.9 g overall (CI, -2.5 to -1.2 g; P < 0.001). Mean trans fat per 1000 kcal decreased by 2.7 g per 1000 kcal (CI, -3.1 to -2.3 g per 1000 kcal; P < 0.001). Purchases with zero grams of trans fat increased from 32% to 59%. In a multivariate analysis, the poverty rate of the neighborhood in which the restaurant was located was not associated with changes.

Limitation: Fast-food restaurants that were included may not be representative of all NYC restaurants.

Conclusion: The introduction of a local restaurant regulation was associated with a substantial and statistically significant decrease in the trans fat content of purchases at fast-food chains, without a commensurate increase in saturated fat. Restaurant patrons from high- and low-poverty neighborhoods benefited equally. However, federal regulation will be necessary to fully eliminate population exposure to industrial trans fat sources.

Primary funding source: City of New York and the Robert Wood Johnson Foundation Healthy Eating Research program.