moderato. adv. 1. (Music, other) at a moderate tempo. 2. (Music, other) (preceded by a tempo marking) a direction indicating that the tempo specified is to be used with restraint: allegro moderato.
While celery is a very low-calorie food, it likely doesn't provide you with negative calories. Mayo Clinic suggests that while it's theoretically possible for negative-calorie foods to exist, there are no reputable scientific studies that prove certain foods cause negative calorie effects.
Therefore, if you're expending -- and eating -- 2,000 calories in a day, your body burns about 200 of those calories eating a digesting food. Therefore, if you're eating a 6-calorie, medium-sized celery stalk, your body will burn almost 1 calorie eating and digesting that stalk.