“Now the Spirit expressly says that in later times some will abandon the faith by devoting themselves to deceitful spirits and teachings of demons, 2 through the insincerity of liars whose consciences are seared,3 who forbid marriage and require abstinence from foods that God created to be received with thanksgiving by those who believe and know the truth” (1 Timothy 4:1-3).
The warning starts by saying in verse 4:1 “some will abandon the faith and…” which means they will no longer believe in God or follow the example of Jesus. A Christian Vegan who shows love for their animal neighbors BECAUSE OF THEIR FAITH would therefore not be included in this warning. People often misinterpret this passage to mean that anyone who forbids eating certain foods is possessed by a demon, but if this were true, then God would be condemned because in Eden that was in fact the one thing God did – forbid from eating from a particular tree. Clearly God is not possessed by a demon. Therefore the forbidding of certain foods is not sufficient to prove the person has a demon. It only refers to people who have “abandoned the faith” as it explicitly states at the beginning of the passage.