Every time i go to the doctors office they give me all these medications but never mention how i can prevent future diseases?

Doctors are official drug dealers 
be careful

I can tell you how to prevent diseases.
Avoid wlan radiation. Support your body with all necessary vitamins, minerals and trace elements - the diet today does not provide enough. Detox the body from chemicals and heavy metals. 
edit: there is no point in asking a common doctor - they are idiots.

You need to ask them. A lot of people already know how to prevent "future diseases". Either ask or just google stuff.

Have you tried asking them?

Doctors can be lazy like anyone else, And, sometimes throwing medicine at people is much easier (and time and cost effective) than educating or getting to know patients. And, lets face it, doctors are often very sweet kind people, but not the best communicators. And, yes, they get pharmaceutical reps pushing drugs on you, through them. And they can be the easiest targets and pushovers from a sales perspective. 

The pharmaceutical industry is corrupt, along with the insurance industry. And now hospital chains and medical groups are big corporations, too, wanting their own piece of the pie of the great American healthcare economy. So, don’t blame it on the doctor, or even their little branch or office. Blame it on our messed up healthcare system. We need more qualitative and collaborative care, with doctors and nurses talking to each other and making decisions together, based on science, and not on bottom line or what insurance covers. 

Unfortunately, patients really need to educate themselves, in order to protect oneself from the aggressive marketing, and because doctors can’t always do that. Whenever you think of health questions you have, write them in a note on your phone, then bring that note with you to your appointment. Doctors are better at answering specific questions, or might be better at steering you to the right information. Usually they are trying to act in your best interest. But, if they are giving you a newer or particularly expensive medication, ask them why they chose it. Then ask them if there is an older less expensive alternative that is tried and true. Make sure the pharmaceutical companies aren’t using you like a guinea pig. Also, know the purpose of all your medications. Ask the doctor what, if anything, you can do, to decrease the chances you will need that medicine in the future. Good luck. 👍🏼 

That is actually a difference between MD's and DO's. MD's are the ones that prescribe you medication and get your symtopms away.

DO can do the same thing as MD's, but they focus more on preventing it from coming back. They exam your lifestyle and environmental factors that could have started the disease and try preventing you from doing those kinds of things. 

Unfortunately DO is new and not alot of people know about them. But they are better in my opinion.