We have it on experience (our own and thousands of others) that the following food and situations have no calories to speak of (although the knowledgeable might describe them as unspeakable calories.)

OTHER PEOPLE'S FOOD: A chocolate mousse that you did not order has no calories. Therefore, have your companion order dessert and you taste half of it.

INGREDIENTS IN COOKING: Chocolate chips are fattening, about 50 calories a tablespoon. So are chocolate chip cookies! However, chocolate chips eaten while making chocolate chip cookies have no calories whatsoever. Therefore make chocolate chip cookies often but don't eat them.

FOOD ON FOOT: All food eaten while standing has no calories. Exactly why is not clear, but

CHILDREN'S FOOD: Anything produced, purchased or intended for minors is calorie-free when eaten by adults.

UNEVEN EDGES: Pies and cakes should be cut neatly, in even wedges or slices. If not, the responsibility falls on the person putting them away to "straighten up the edges"