From Bubble Gum Science by Klutz Publishing, 1997, ISBN 1-57054-134-5.
The question mark is because I don't remember who the factoid is actually referring to. I was browsing this book in a bookstore, and scribbled down the pertinent info on a scrap of paper. My actual note says only "444 pieces of bubblebum chewed per second". I suppose I could have just put that exactly, but it sounded funny that way.