Did you know, that the calories in prepackaged meals are higher that what is stated on the package? I had read that somewhere so I decided to test the theory. I looked my LC panini, on the box, it says 340 calories, that is for a weight of 170grams. I weighed my panini, no packaging and it is 188grams. So that makes the calorie count 376

Yes, it is up to us to check and double check.

FWIW, NO calorie count is exact, on a prepackaged food or otherwise. The specific nutrients in a chicken breast, for example, are dependent on how it was raised, what it was fed, and for how long...these can change protein and fat ratios, making that chicken breast higher or lower calorie. The nutrients in a vegetable change based on what they can pull from the soil, how much sun they get, and how much sugar they develop. So even while a "typical" cup of carrots will have a certain number of calories, your particular carrots may be higher or lower, depending on how and where they were grown.

So calorie counts can vary from what is on the package of packaged foods (the package weight can vary 5-10%, and there's another variance to account for the factors mentioned above), but it isn't just packaged foods. Food is sort of inherently variable in that regard. We can do our best to diligently and exactly count calories, but we are always going to be off in one way or another because food isn't that predictable.

You know, I never thought about weighing it to make sure it's correct. It certainly makes sense, though. Easier done with a panini than with an entree--how do you take into account the container? Perhaps weigh and then weigh again when it's empty and do the math?