@kdfrawg The problem is that you don't expend nearly as much energy as you think by exercising. There are other reasons you should exercise, of course, but exercise alone won't make up for a poor diet.
While I understand how society views it, I don't consider fasting extreme at all. In fact, it's a perfectly natural phenomenon. Think about what a bear does: it eats a lot during the spring and summer months, fattening itself up before it goes into hibernation for several months. During that time? The bear is definitely not eating. What keeps the bear alive? Stored body fat.
We have a 24x7 all-you-can-eat buffet at our disposal. We can eat and eat and eat, but unlike bears, we don't hibernate. Instead, we keep eating and get things like Type 2 Diabetes.