I posted something similar to this in a different forum, but I thought it was worthy to be posted here as this is what we do.
My latest Consumer reports magazine did a study on some nutritional guides that restaurants put out and what their food actually contains. Some were higher and some were lower.
For example, Olive Garden lists it's Lasagna Primavera with chicken at 420 calories. When CR tested it, they found it anywhere from 508 - 585.
Or another, Outback Grilled Chicken on the barbie. Listed - 401, actual 391 - 511
At least a big mac is less... listed - 550, actual 520 - 528
I guess the point is, just realize what you eat out can be over or under by 100 calories when you count it.