Chewing your food doesn't only slow you down so that you eat less, but helps you produce more saliva which counteracts stomach acid. Chewing gum may also help with reflux unfortunately there's a lot of either sugar or artificial sweetners in the stuff to partly counteract the beneficial effects of extra saliva. After all, we don't want to get cavities either, which like heart disease and cancers were less known to almost nill generations back. That comes from a big sugar thing this society has today.