And, to meet the demands of top-flight rugby, it was not uncommon for players to try to get themselves into the required shape in their off-season.
Since the end of last year's Tri Nations, several players had been in the gym and working on their diets, and they had put on weight.
It wasn't a case of putting weight on for weight's sake. It was to develop lean muscle in the right areas.
"These guys are talented rugby players, but if they're a bit smaller they're struggling against bigger men. If we can get them up to the size of the opposition they're going to face, and still keep the talent they have, their explosiveness, we are going to have a heck of a rugby player – the type that we need at our level to compete," he told the All Blacks podcast.
Some times adjusting to the changed body weights affected the way players were able to respond with inevitable claims of being unfit.
"Smaller players struggle to carry that weight. [Hooker] Dane Coles was an example when we first picked Colesy years ago. He had some weight put on him, and, for half a season, he struggled like hell to carry that weight. Then he got used to it, and he was away.
"That was when we first picked him and look what he's like now. Pretty special," he said.
Fox said with Sky Super Rugby Aotearoa underway some All Blacks, who had longer breaks out of the game, took time to build to their best. But in the meantime, younger players stepped up for their chance to push for consideration.
The All Blacks' selectors were aware of those issues.
Fox said when choosing their sides the selectors were not only looking at Super Rugby form but also at past performance and how certain players had performed at the top level.
But sifting through talent to choose a team brought its issues.
"It's hard when you know guys have worked their backsides off and they don't get their name read out but our history is littered with that. It just makes a lot of them react well to it, they just work that little bit harder," he said.