Researchers at Tufts University bought 29 dishes from 10 restaurant chains, including Ruby Tuesday, McDonald’s, and Wendy’s, and analyzed them to see whether the menu calorie counts were right. Turns out that on average, the tested dishes contained 18 percent more calories than the amount listed. The differences ranged from 36 percent fewer calories to a jawdropping 200 percent more! Denny’s grits topped the higher-calorie list, thanks to what turned out to be a supersized portion.

It wasn’t all bad news—the Taco Bell nachos, P.F. Chang’s Cantonese shrimp, and Domino’s thin-crust cheese pizza had around 30 percent fewer calories than the menu listed. Bear in mind that researchers sampled just one of each item and that all were purchased in the Boston area; calories might well be different if you order the same dish in your local joint.