The myth of negative-calorie foods is deeply seeded in our thoughts (or hopes) that chewing food and slow digestion burns tons of calories--or at least enough to negate really low calorie foods. Hmmm. Well, as it turns out, neither of those activities do squat. To be honest, I can't recall the last time I broke a sweat chewing something.
I'm not all that bummed. You may be, but the only times I think I have ever really eaten celery over a long span of time was in Rochester when I would order wings from Pontillo's. And even then, celery was more of a spoon to eat blue cheese than a vegetable.