Have you ever wondered what it would have been like to sit and be taught by Christ in the flesh? How awesome it is that the Holy Spirit did as Jesus promised and brought to mind everything Jesus had taught them so they could pass those teachings to us in the New Testament!
On the other hand, what kind of teachings would we hear if, instead of Christ, a deceiver who had gotten his teachings straight from demons tried to pass him or herself off as a messenger of God? What kind of things would they teach as doctrine? Thankfully, the Lord, through the apostle Paul, told us how to recognize demonic deception when we hear it!

“Now the Spirit expressly says that in later times some will depart from the faith by devoting themselves to deceitful spirits and teachings of demons, through the insincerity of liars whose consciences are seared, who forbid marriage and require abstinence from foods that God created to be received with thanksgiving by those who believe and know the truth. For everything created by God is good, and nothing is to be rejected if it is received with thanksgiving, for it is made holy by the word of God and prayer.” (1 Timothy 4:1-5 ESV)

Paul here says what is at stake if we are deceived. It constitutes “departing from the faith” and we must be on our guard to make sure we don’t let it happen to us or those we love. But how do we recognize such teachers? How do we discern that someone is a liar with a seared conscience? By what they teach as doctrine.
1. They teach abstaining from marriage. This can apply to two different types of teaching. First and foremost in the history of the church is the teaching of celibacy. While some choose to remain single, to bind upon those who would be elders (bishops) a requirement of celibacy flies in the face of the qualification listed in 1 Timothy 3 and Titus 1 that they be the husband of one wife and rule their households well.
But the other, contemporary application is those who teach that physical intimacy is permitted before marriage. They even recommend living together to see if couples are sexually compatible. By advising couples not to marry, they teach doctrine that Paul describes as demonic!
2. They teach that dietary laws are binding for today. Now please don’t misunderstand me. If you choose to follow a kosher, vegetarian or vegan diet for some health benefit, you are free to do so. You can even tell others how you think it is healthful to do so. But when anyone begins to advocate these dietary choices because it is a command of God, they have crossed over into the demonic. I know that sounds harsh, but don’t blame me. I’m not the one who wrote it!
In fact, these verses loose us from all dietary restrictions, as long as we receive the food with thanksgiving, because God has said we can eat it, and we have prayed over it. What more reason do we need to pray before meals? But remember this is for those who know the truth. A weak brother or sister that would be made to stumble is more important than exercising our rights to eat whatever we are served!

I would encourage you, if any of the demonic teachings described here sound like what you are being taught, to get out of there right away. Doctrines of demons are spiritually poisonous and lethal to your soul and your diet needs to change if you are to survive!