More than anything else, your health is what you need most, or so people say. I'd say that's true as well. If you aren't healthy, your life will most likely be miserable. In an environment such as the one we live in today, it's getting increasingly difficult to get and remain healthy. There are bad foods, bad lifestyles all around you no matter where you look. How can you be healthy in such a case?
It starts with your approach. You have to practice a lot of discipline and control if you want to avoid fast food. Fast food - as unhealthy as it is - is available everywhere and that contributes to its popularity. Since your diet is very important, it is imperative that you pay attention to it. Unfortunately, many don't.
You may look into getting some help from a dietician too, especially for some guidance as to what to eat and when. You can find a number of plans on the web to help you out too. Of course, they aren't going to help you do anything - if you need some diet ideas though, they can be great. Unless it's absolutely severe, I won't really go for a dietician but if it is, I won't hesitate either. It might be expensive but spending on your health is absolutely worth it.
Other than your diet, you need to exercise regularly too. That, too, is very rare and thus, most people you see around are unfit in one way or the other. Being active and exercising every day - or even every other day - will help you keep your body in shape. Exercises coupled with good diets are the best way to get healthy.
Being healthy from the outside doesn't matter as much as being mentally healthy does. More often than not, it means an organized life - one that isn't chaotic. Meditation can also help. Meditation, it is believed, can be really helpful. There is scientific backing, too. Getting plenty of sleep and drinking ample water is also important. The smallest things, those that you won't even think of, matter more than anything.
It might be a herculean task for you but not impossible. You will need to do more than just diets and exercises. You need to be very patient and persistent. Being healthy won't be easy. You need to be persistent, as I said, and can't cut corners.