Actually, you need to take the psychological principle of classical conditioning and mix it in with a bit of biology. For guys, the body runs most optimally on 6 smaller meals a day, spread out roughly every 2.5 - 3 hours (for women, it's 5 smaller meals and a bit more time between). When your digestive system has smaller amounts of food to digest more consistently, it is metabolizing food all the time, yet because it's less food you aren't going to get fat. Eventually, when you combine this with exercise, over time your body will come to expect you to eat these 6 meals a day (read about Pavlov and Classical Conditioning to gain understanding on why your body starts expecting this), and your metabolism has thus picked up speed.
To sum it up, contrary to popular thinking, you need to eat more, but in smaller portions and more times a day.