So tend to your knitting. You've got your hands full just taking care of your own life before God.
Forget about deciding what's right for each other. Here's what you need to be concerned about: that you don't get in the way of someone else, making life more difficult than it already is.
I'm convinced - Jesus convinced me! - that everything as it is in itself is holy. We, of course, by the way we treat it or talk about it, can contaminate it.
If you confuse others by making a big issue over what they eat or don't eat, you're no longer a companion with them in love, are you? These, remember, are persons for whom Christ died. Would you risk sending them to hell over an item in their diet?
Don't you dare let a piece of God-blessed food become an occasion of soul-poisoning!
God's kingdom isn't a matter of what you put in your stomach, for goodness' sake. It's what God does with your life as he sets it right, puts it together, and completes it with joy.