Why do I have a bad breath?

I'm a 16 y/o teen and I have always wondered why does my breath smell bad like 85% of the day?When I wake up in the morning,yeah...Its normal to smell bad so I brush my teeth and the smell is still bad and It continues for the rest of the day and It changes with what I eat and so on.I can call myself healthy,I dont do drugs neither smoke,I'm involved in cycling and I'm pretty active.I brush my teeth twice a day but the smell is pretty bad.I havent used a mouthwasher product yet.

Can your dentist not offer any advice hear? i know its not nice to have this problem. 

 

I think bad breathcan also be made worse by the types of foods you eat and other unhealthy lifestyle habits. Check with your dentist, they give you advice.

I forgot to mention to mention I had braces about a year ago which I think It's what changed the smell but I'm not sure.