The theory behind zero calorie or negative calorie foods is that they contain such a scant amount of calories that the energy you expend eating them cancels out their calories. In essence the bottom line is that you don’t take on any excess calories, and in some instances you end up burning calories as you eat them. Whether or not this is an accurate statement, it’s clear that the following foods have such a slight caloric load they won’t put a dent in your daily total.