This month in the Journal of the American Dietitics Association there are many interesting findings noted including Urban et al's article on The Accuracy of Stated Energy Contents of Reduced-Energy, Commericially Prepared Foods(Jan 2010). The articles mentions that the average amount that foods are underestimated is 18% MORE than the stated values(aka the amount of calories in the packages and in restaruants portions were less than the amount actually in the package or meal). One of MY go-to's in a pinch: Bell and Evan's gluten free chicken tenders was even on there! Again, as mentioned it wasn't a LARGE difference but enough to count per serving. A few of the restaurants included in the study were Wendy's, PF Chang's, Domino's, Ruby Tuesdays, and Denny's and all overall were underestimating caloric amounts of their foods.
I attached the entire article below: