Of all the Bible translations, I think the HCSB puts this in the clearest way I've seen. Most other translations render it as something like "though I give my body to be burned". I never fully understood how Paul was presenting feeding the poor as a bad thing. I had ideas, but the HCSB rendering puts it in a way that can be understood by anyone. It is, as I had suspected, self gratifying charity against which he was speaking.
Needless to say, there is a way to be selfish in charity. Real charity focuses on the recipient. You're hungry, I will feed you. You're naked, I will clothe you. You're in prison, I will visit you. In these situations, the one in need should be the one who benefits. But it is possible to do these things for personal gain. Some do it for money. Some even do it to money launder (the concealment of criminal origins of financial gain, e.g. setting up a church to claim money made by selling drugs was actually donated by willing parishioners). In Jesus' day, the Pharisees were notorious for blowing a trumpet in the synagogues and in the streets, letting everyone around them know how charitable they were.
In these cases, charity is worth nothing. It benefits the recipient, sure, but this becomes a side effect, when it should be the goal. And so Jesus says something quite profound: When you do a charitable deed, don't let your left hand know what your right hand is doing (Matthew 6:1-4). I like to say it this way: We should do good in the same manner as a criminal does evil. Put your money in the charity box as secretly as if you were trying to steal the charity box. When you do good, be sneaky. If it's more about you than about the recipient, or about God, you're doing something very wrong.