NEW YORK — Mean trans fat per restaurant purchase decreased by 2.7 grams in New York City in a study examining consumption before and after the city restricted the use of artificial trans fat in restaurants. Results of the study appeared on-line in the Annals of Internal Medicine.

The cross-sectional study from the New York City Department of Health and Mental Hygiene included purchase receipts matched to available nutritional information and surveys of adult restaurant customers at lunchtime. The researchers randomly selected 168 New York City restaurants from 11 fast-food chains.

The final samples included 6,969 purchases in 2007, or before the trans fat restrictions were in place, and 7,885 purchases in 2009, or after the restrictions were in place.

Mean saturated fat intake per purchase increased by 0.55 grams from 2007 to 2009. Mean trans fat plus saturated fat intake decreased by 1.9 grams. Purchases with 0 grams trans fat increased to 59 percent in 2009 from 32 percent in 2007.

New York City and the Robert Wood Johnson Foundation Healthy Eating Research program provided funding for the study.