A study by Tufts University that sampled food from 42 restaurants found wide discrepancies in the calorie count posted on the menu-- especially at sit down restaurants, and, surprisingly, most often on the diet side of the menu.
"These were the foods that people who are trying to manage their weight would gravitate towards and they may be getting more calories than they expect," Lorien Urban, Tufts, said to ABC News.
A just-completed ABC News sampling found that more than half of the low-cal meals we tested had more calories than listed on the menu. A nationally known lab tested 24 food samples from four sit-down restaurants and one McDonald's. The Big Mac had 30 calories less than advertised on the menu. Eleven meals on the sit-down menu had more calories than advertised on the menu, and 10 had fewer. Only one calorie count was the same.
The ABC samples showed The Cheesecake Factory's fish and chips had 420 calories more, Olive Gardens' seafood brodetto was 180 over, and Chili's margarita grilled chicken was 120 calories over the advertised count.
"That may not sound like a lot, but if someone were to consumer 100 calories extra a day for a year, they could gain up to 10 pounds," Urban said.
All the restaurants and their trade association say that most calorie counts are as accurate as possible and tested extensively to make sure. But they concede there are variations, mostly due to portion size and individual restaurant preparation. The menus warn actual calories may vary.