Raspy voice, Important to Sioux, Didn't win the race? Oh well, strong glue

I begin with ambition and good intentions, then quickly turn into wheezing negotiations. I promise health, deliver sweat, why do people do me on purpose?

Hey, you're about to go on stage! What's that on your coat? Don't ask, I feel really sick, I can't even remember what I wrote. Calm down, man, you got this! One second, it's hard to get the red out, Yeah, my mother made her famous pasta sauce, man, I don't know if all this is worth the clout, I'll tell you the best advice I ever got, Lose Yourself

You can find me in burgers. You can find me in tacos. I'm not a vegetable. But, I'm also not a fruit. I'd ask you to get into the meat of this riddle. But that's not relevant either, is it?

Hark! Dost thou seek the silent sage, Who whispers wisdom from the page? A kingdom bound in leather's clasp, Where ancient tales are thine to grasp.