Fair point.
Well no, not really (to be serious). I think something akin to the traffic lights system would be of more use, although I don’t think actual traffic lights would be a good idea. Who’s going to order anything with a red light?
I think something like a slice of cake representing the number of calories as a percentage of your daily recommended intake would be better e.g. a slice that was a quarter circle would mean the dish is a quarter of your recommended intake and the Tiramisu would be about three whole cakes (if made properly).