What are Christians not allowed to drink?

Answer:

There is nothing known to be harmful about coffee. The Bible doesn't talk about coffee. Where it is generally applied is to harmful substances, so something like tobacco would violate: "Or do you not know that your body is the temple of the Holy Spirit who is in you, whom you have from God, and you are not your own? For you were bought at a price; therefore glorify God in your body and in your spirit, which are God's" (I Corinthians 6:19-20). This passage is about sexual sins, but it does lay down a principle in its reasons against sexual sins.

There are no dietary restrictions on Christians. "Now the Spirit expressly says that in latter times some will depart from the faith, giving heed to deceiving spirits and doctrines of demons, speaking lies in hypocrisy, having their own conscience seared with a hot iron, forbidding to marry, and commanding to abstain from foods which God created to be received with thanksgiving by those who believe and know the truth. For every creature of God is good, and nothing is to be refused if it is received with thanksgiving" (I Timothy 4:1-4).

The one big restriction on Christians is not to take anything that clouds your thinking. "Therefore let us not sleep, as others do, but let us watch and be sober. For those who sleep, sleep at night, and those who get drunk are drunk at night. But let us who are of the day be sober, putting on the breastplate of faith and love, and as a helmet the hope of salvation" (I Thessalonians 5:6-8).