We used to have guinea pigs, and one or two of them liked nothng better than a good knaw at paper. They had a very varied diet, and were very healthy, they just seemed to like eating paper! Did them no harm, the only problems were if you left any paper within tooth reach, it got gobbled- unread newspapers, bills, homework books, the lot!
Still it was better than the one who liked eating rubber and soft plastic, electric cables and buttons on remote controls were especially favoured!