Sin. I'd benefit from understanding sin better. Evangelicals are to content to say something is sinful simply because the Bible tells us so. That's fine for a start, and a good "reduced form" as we say in economics. And I agree with Ockham that it is God saying something is sinful that makes it sinful, rather than God looking at something, seeing it is independent sinful, and therefore so naming it. Murder is because God says it is; God doesn't necessarily say it is sinful because it is. But there are also natural law reasons for why most sins are sins, reasons not based on divine revelation. Murder is an example-- there are good natural law reasons for it to be considered bad. But we should also look at lust, gluttony, sodomy, greed, sloth, and so forth.

Gluttony is an overlooked sin. Why is it sinful? What is it, exactly? Here are three possibilities.

1. Gluttony is poor stewardship. If I eat a lot, somebody else doesn't get to eat as much.

2. Gluttony is bestial. I degrade my humanity, and pollute God's image, by stuffing myself and by making myself fat.

3. Gluttony is distracting. I put food before God, both in my attention and when it comes to conscious tradeoffs.

These all have different implications. Thin people who don't eat much can be guilty of Type 1 and 3 gluttony.