system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How are pickles 0 calories?
gpt
So, in the US, the law says that if a thing has fewer than five calories per serving, the company is allowed to round that down to zero. Smaller pickles have a little less than five calories, so the companies round that down.

Flavored water is the same way. A typical one liter bottle of flavored water e.g. Clear American, has about ten calories to the bottle, and three servings. But if you divide ten by three, you'll note it's less than five. And therefore, the company can put it down as 0 calories.

As an interesting side note, the law also says that if a thing has less than point* five grams of sugar per serving, the company can round that down to zero as well. Which usually isn't a problem, except that tic-tacs (the brand of mint) are almost pure sugar, but have a total weight of less than point* five grams, and therefore they're advertised as having '0 sugar'.

[edited to correct a magnitude error, thanks gigantic_idiot].