If you're a distance runner, this kind of thinking is pure hogwash. You heard me. Hogwash. When you run more and run longer, your body needs more fuel. Not only does it need fuel during the run, it also needs you to replace that fuel after your run. I've realized that thinking of my food as fuel helps me get beyond the idea that I'm over eating. If I'm training hard and I'm hungry, that's my body telling me I need fuel. I've also realized that I can avoid that constant hungry feeling by eating more often throughout the day.
Basically, it's all about putting back the calories you've expended. For me, eating more often throughout the day seems to help achieve this. I'll eat breakfast (an English muffin with peanut butter and preserves); then around 10:00AM I'll have a mid-morning snack (usually a handful of almonds or a granola bar). I'll eat a regular lunch; then by 2:00PM, I'm ready for a mid-afternoon snack. I'll have a regular dinner and then a few hours after that I'll have a snack of yogurt and granola or something similar. The more frequent smaller meals works for me, but for another runner, having three larger meals and no snacks may work just as well. It doesn't really matter as long as you're taking in the needed calories to sustain your normal body functions plus the extra caloric demands from your training.
I weigh around 138lbs. A person my size needs about 1,400 calories just to live and breathe (Resting Metabolic Rate). Since I'm a pretty active guy during the day (not including any running), I'll need an additional 700 calories. Someone my size burns about 110 calories per mile. So, for a 10-mile run I'll need an additional 1,100 calories. So for a day in which I'm running 10 miles I need to make sure I eat about 3,200 calories. On a day with an 18-mile long run, I'd need to eat about 4,300 calories. No wonder I'm so hungry! But telling a weight-conscious person he needs to eat 4,300 calories can really freak him out. That's why I like to think of it as fuel. It's like putting gas in your car. You may only use 2 gallons of gas to drive to and from work, but if you're traveling out of town on a business trip, you'll use the entire tank.
So, the moral of this story is—Train Hard, Eat, Drink, and be Happy!