When you eat something, it provides calories, but to burn food, your body also burns calories. If your body expends more for combustion than you take in, then there would be negative calories. Does that really exist?
Celery is one of the ingredients that is sometimes said to provide negative calories. Energy is indeed needed to digest food, but it is so little that it does not outweigh the calories you consume. Unfortunately, negative calories do not exist.
Put that celery away.
