Rapper Mack 10 -- I'm Not Fat Anymore!!!

Double beef patty, special sauce? Not for Rapper Mack 10 ... who axed Big Macs (and pretty much all things cow) from his life ... and lost an incredible 60 plus pounds in the process!!!

The "Westside Connection" rapper's been HUGE since the mid '90s ... so after our photog spotted him out in L.A. last week (above) looking svelte, we contacted him to find out what's up.

Mack tells us ... he's majorly slimmed down by cutting all red meat from his life -- "I used to love to be able to order a burger or get a fat ass steak, but now I am up on eating fish, chicken and s**t."

FYI -- At his heaviest Mack was 267 and now he's South of 200.

Mack says it's all thanks to his kids -- "I want to make sure I can keep up with them. It's hard to eat healthy but that's something I got to do to make my life right."

We'll bow down to that.