Earlier quoted context omitted.
Some people can eat something immediately after exercising, some can't. When I run in the morning I usually rest for a few minutes to cool down, take a shower and then have breakfast. But you can eat immediately after you finished exercising if you feel like it.
If the theory is right it's better to wait longer, as it takes time for your body to re-stock the glycogen reserves. So you are still burning fat after you finished exercising.
Also, keep in mind that while depleting your glycogen stores may help your body focus on using fat instead of other sources of energy during exercise, it doesn't change the fact that the only way to lose weight is to eat less than you use. Too many people look at these studies (GI, insulin response, and HFCS immediately come to mind) as silver bullets. The only real silver bullet is eat less than you use. There was an article not long ago about a guy who only ate twinkies and lost weight by counting calories.
Physically, losing weight is pretty basic stuff, but it's so hard to do because it requires a tough combination of mental and emotional skills and often requires people to change their deep seated (often decades long) relationship with food.