WATCH WHAT YOU EAT

How would you like to know exactly how many calories you've just eaten after a meal?
That happened last weekend. Tanya and I dined at a restaurant on Sunday, and along with the bill came a printout showing exactly how much we had eaten, broken down into salt, fat, calories, etc. It also came with subtle recommendation that we'd eaten a little too much and should spend an hour walking it off. I should say that although it was just the two of us, we'd also ordered some food to take away for Tanya's parents so it wasn't as bad as it sounds. Certainly 1,800 calories between four people is better than just between two.
How would this go down in other parts of the world? Is it already happening?
Personally I think it's a great idea and makes you think more about what you're eating.