He has done that - proved beyond any doubt that he's heavily into being an All Black. The first sign of the turnaround came in Johannesburg, when his impact off the bench was significant.
He made one huge tackle where he drove a handful of Springboks a good five metres back over their tryline to force an attacking scrum. Against the Wallabies in Brisbane there was more big ball carrying and defensive grunt; in Chicago he was probably man of the match and at Twickenham his first test try was testament to his level of involvement and contribution.
Tough love worked its unorthodox magic and now Faumuina's considerably smaller backside is in no danger of being kicked by anyone.
Faumuina is an increasingly important part of the All Black operation.
The traditionalists still see rugby as a starting XV and a bench, but the All Blacks don't. They have come to see the squad's two specialist tighthead props - Faumuina and Owen Franks - as a combination, with the former, given his mobility and ball skills, more suited to playing off the bench, when there is typically more space.
When he wasn't fit enough, the frustration for the coaches was considerable
"I was probably eating too much, I think," says Faumuina. "I think I just got too comfortable. And when you get too comfortable, you don't sacrifice things. You don't push hard enough at training and stuff like that."
Speculation has surfaced that he may not be playing in the black jersey beyond next year, with reports linking him with a move to Racing Metro in Paris.
"No ... that's the first I had heard of it," he said when asked whether it was true that he had already signed.
"I'm enjoying my time with the All Blacks and playing for the Blues. We will see how it goes when the time comes [to extend his contract]."
