Off-Topic: Hungry?

So, a little background. I'm currently dieting, and it frankly sucks. But, this got me thinking. I don't often take advantage of the mechanics of hunger in my games. Let me elaborate.

Say you have a group, and they are stalking a mark. They've got some downtime parked in the team Riggers van. As the hours pass the team gets hungry, tired, thirsty, has to find a restroom. Their effectiveness wanes. They, quite simply, aren't as fresh, or observant, as they could be.

I thumbed through the rules last night and I couldn't find a good set of modifiers for being hungry. This seemed like an oversight to me. If you have a character with a Squatter/Street lifestyle, meals might be few and far between, and most likely not terribly filling. How does that effect the player?

This lead me to another great thought. We've all had that player that picks up a month of Squatter lifestyle to begin the game, simply to 'get by' as he didn't want to spend the money on something better. So, he shows up to a meet, unwashed, clothes are wrinkled, he's most likely unshaven, and rank. He's hungry, and cold, running on minimal sleep this should, in my mind, effect his rolls, how he's perceived, and even if he can get to the meet.

For example, Mr. Johnson is at a corner table in a swank restaurant. A scruffy looking bum isn't even going to make it past the door, let alone to the table. Heck, in certain parts of Seattle a reasonably well dressed middle-aged man wouldn't make it to the table without jacket and tie.

So, here's the challenge I have. In the comments, let me know if you handle hunger, or appearance, in your games? If you do, what rules do you use? What's your gut feeling as a GM?

I think, at the very least, it might help to toss some ideas around. Remember, as always, comments are moderated but I try to keep up on them, so there shouldn't be much of a delay.