Neurologist Dr. Fred Baughman talks about the fraud of ADHD and the poisoning of U.S. children
See if you can eat better first.
Take up something like learning to sing or play an intrument, or group dancing or tai chi/yoga. Something that would require you to focus and the group will carry the focus some too.
Or go to a classical concert and really listen to the whole piece of music, as much as you can. When you listen see if you can hear the sound of the music in your head - follow the sound as it were.
Or just find a live band in a local club and bust a move to a couple songs. That would traing you to stay focused for the length of one song, of you grove out to it the whole way through and sometimes the loudness of a rock band is something that will demand your attention so you won't be able to wander.