In theory, no. With the number of calories in a stick of celery compared to the number of calories that you burn off from doing nothing but chewing and swallowing for the duration of the celery stick, then you would have the following sum:-
ak+1 = 2 (1 - 1/22k)/2 (1 - (1 - 1/22k)/2) = (1 - 1/22k)(1 + 1/22k)/2 = (1 - 1/22k+1)/2
Actually I just made that sum up (hehehe). But I believe that a celery stick has more calories than is burnt off by the act of eating it. But like Clanad's link suggests, you are likely to be burning off other calories whilst eating it.
I hope that clarifies. :o)