system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How can nonstick cooking spray have zero calories if it contains oil which is usually high in calories?
gpt
If you are American it is probably down to the regulations over food labelling. 

For example, Tic Tac mints contain sugar. However, since the amount of sugar **per serving** (1 mint) is less than 0.5 grams, FDA labelling requirements permit the Nutrition Facts to state that there are 0 grams of sugar per serving.