I find it amusing to think that a cotton shirt is a plant product, while gourmet sea salt is a mineral, not a food, yet I think they would expect the salt declared but not the shirt.

If you read the ingredients of a candy bar, you will find things like dairy ingredients and sugar, which are of animal or plant origin.

Given that the couple of times I did take candy and such entailed a 10-20 minute delay for an indifferent but officious once-over, my usual practice is to avoid travelling with items I need to call "food". They almost always have food where I'm going.