Go with Scripture and your conscience. If I could be so bold, I would also say, stick to New Testament on things like that. The New Testament specifically warns many times to not associate with sexually immoral people who call themselves Christian brothers (and sisters) 1 Cor chapter 5. Fatness is not condemned the same as sexual sins. Again, go with your conscience and OBEY scripture. "The man who says, "I know Him," but does not do what He commands is a liar and truth is not in him." 1 John 2:4.The reason I don't associate with adulterous, lying churchgoers who say they are Christians is because the bible says not to do it. Jesus tells us what to do about sinning brothers (in Christ) in Matthew 18:15-17: "If a brother sins against you, go and show him his fault, just between the two of you. If he listens to you, you have won your brother over. But if he will not listen, take one or 2 others along, so that every matter may be established by the testimony of 2 or 3 witnesses. If he refuses to listen to them, tell it to the church, and if he refuses to listen even to the church, treat him as you would a pagan or a tax collector." Here's another good Scripture, "But mark this: There will be terrible times in the last days. People will be lovers of themselves, lovers of money, boastful, proud, abusive, disobedient to their parents, ungrateful, unholy, without love, unforgiving, slanderous, without self-control, brutal, not lovers of the good, treacherous, rash, conceited, lovers of pleasure rather than lovers of God- having a form of godliness but denying its power. Have nothing to do with them." 2 Tim 3:1-5Respond in obedience, in love, in gentleness. Many times, rebuke does not seem loving, even though it is. We must love, and love others, but not seek peace with man so much that we dishonor God. Even gentle Jesus used a whip to rebuke the church. John the Baptist called religious leaders "vipers." They did not shrink back for fear of rejection from man. (I am not emphasizing gentleness so much here, because that is not really a problem in the American church. So many of us are "people-pleasers" (me,too) and we need a little more encouragement to be truthful and obedient to God's word, we are gentle and loving to the point that we often fail to do anything that might hurt someone's feelings for a little bit.)This kind of stuff is hard to obey, but obedience to God is love for God, "We know that we have come to know Him if we obey His commands." 1 John 2:3Praise God! I pray these Scriptures will be helpful, and I pray our Lord Jesus be exalted!