"I was in the wilderness. And I probably should have left a trail of breadcrumbs. But you found me," Fraser told director Darren Aronofsky.
"If you -- like a guy like Charlie who I played in this movie -- in any way struggle with obesity, or you just feel like you're in a dark sea, I want you to know that if you too can have the strength to just get to your feet and go to the light, good things will happen," Fraser said to a standing ovation.
The Critics Choice Awards are one of a raft of major award shows in the build up to the Oscars, which take place this year on March 12.
Surreal sci-fi "Everything Everywhere All at Once" won best picture at Sunday's high-profile critics awards, boosting its hopes for the top Academy Award prize.
The film finished the night with the most film wins on five, including best director for Daniel Kwan and Daniel Scheinert, best original screenplay, best editing, and best supporting actor for Oscar favorite Ke Huy Quan.
Among the night's television prizes, the sixth and last season of "Breaking Bad" spinoff "Better Call Saul" finally claimed its first best drama series win, as well as best actor for Bob Odenkirk and best supporting actor for Giancarlo Esposito.
