I would wonder about a mineral deficiency... you might want to have his iron, zinc, and magnesium checked. If it is truly just sensory seeking, and he is willing to try different things, you might want to try thin, dry crackers (like matzo... looks and almost feels like paper). Good luck!

there is also some chewing toys or chewing necklaces...ive seen kids do the chewing straws too.

My 3 year old has recently started chewing paper and other random things that he may find. I just spoke to his OT about this today and she says that it may be sensory related, he may like the pressure that he feels in his jaw from the chewing. She said that I may want to try some chewable jewelry. She also suggested that I try some crunchy foods like raw carrots, pretzels, celery, etc.

My girl started chewing erasers off of pencils.
She is getting her 6 year molars, which may explain the peculiar oral sensory choice.
To me, chewing paper (not eating it) might be his stim. It's relaxing to him, and might be a response to school pressures.

Chewing gum? I mean sugarless and a small portion. My 3 year-old son has had it but he swallows it so I didn't give him more.