Finefeuiaki made his Queensland State of Origin debut this year, after starting all 22 of his matches for the Dolphins and playing every minute.
The 22-year-old has now committed to the club through 2029, signing a two-year extension last week.
His transformation began after joining the Dolphins in 2024, when coach Kristian Woolf challenged him to become a leaner, more durable forward.
At a lunch with Woolf, assistant coach Ben Woolf and CEO Terry Reader, Finefeuiaki recalled, "I had a Scotch fillet, medium-rare, with chips and salad," he told AAP.
"Woolfy was giving me the eye when I ate a lot more of the chips than the salad. He kept saying, 'you've got to eat your greens'."
Finefeuiaki had previously gained weight and subsequently removed the Tongan dish Lu Sipi, made with taro leaves, lamb, onions and coconut cream.
Woolf also demanded more than the bench role Finefeuiaki mostly held during his 37 games for North Queensland.
"Woolfy said he didn;t want me to be a second-option back-rower like I was at the Cowboys, and that he wanted to develop me into an 80-minute back-rower," Finefeuiaki said.
"Credit to Woolfy. Without him I probably wouldn't be here."
Known as "King Kuli", Finefeuiaki now wants the Dolphins to beat the Sydney Roosters in Friday's preliminary final at Suncorp Stadium.
He was inspired by North Queensland's 2015 grand-final triumph, recalling Johnathan Thurston's golden-point field goal.
"It would mean the world to win it here with these boys."