Cycling is one of the best exercises you can do to stay healthy for the long term. It can provide you with a high level of cardiovascular fitness and all of the benefits that brings. But as good as cycling is, it is only part of the equation.
Another very important part of that equation is one very closely allied with cycling: what and how much we eat. Cyclists are well known for eating mass quantities of food. Organizers of bike rallies on college campuses have to really pound into the cafeteria staff what is about to happen to them; first time hosts are still shocked at their bare larders. While we are riding, it is good and necessary to eat a lot. Our problem comes during the week on those days when we are not riding; we've learned too well how to eat mass quantities, and cutting back to "normal" levels is difficult if not nearly impossible for some of us. But continuing to eat at cycling levels on days we are not cycling must inevitably lead to weight gain (not good). This is a difficult fact to accept, but once you do, doing your "pushaways" will become easier.
What you eat is also vitally important to your continued health. You can still drop dead at an early age while cycling a lot and not eating too much if your diet results in clogged arteries or runaway cancer cells. There are many sources where you can learn about what to eat, and what you should eat is not the same for everyone. But for most, just because you ride a lot doesn't mean you can safely eat a gallon of full-up ice cream every week. Check with your doctor, get the facts, stay healthy--we want you cycling for a long time to come!