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.
Foods that contain few calories, such as celery and other nonstarchy vegetables, provide a small number of calories but still require energy to digest. That means it is theoretically possible to have a negative-calorie food, but there are no reputable scientific studies to prove that certain foods have this effect.