I decided my 19th year that I would change a lot of things in my life, like smoking and my weight, while I wasn't deathly big, I was still pudgy.
I didn't quite lose all the weight I wanted to, but I quit smoking and I cut back on my caffeine consumption.
I also had yellow teeth most of my teenage years. I can now say aside from little spots of mild flurosis, my teeth are as white as porcelain and my breath smells good from the thousands of packs of orbit I have chewed since I quit.
I became quite the health nut when I quit smoking. I am still working on the weight, it is an accomplishment to say I weigh less than I did when I was 15. I also cut back on meat. I will never be a vegan, but meat has become a side.
A man has gotta have a steak once in a while.