LAS VEGAS — Bobby Portis — one of the new Knicks who arrived in a free-agency flurry — has become a health-food fanatic and workout demon. He has a stake in a healthy-snack company and is known for his 12-hour workdays in June and July when many NBA players are taking it easy.

That is why, during Dwyane Wade’s miscast 2016-17 season in Chicago, Portis, a 6-foot-11 power forward, got his hackles up when the Miami legend famously called out the young Bulls to the press for not working hard enough after a loss. The next day, a team meeting was staged, with Wade explaining his comments to his teammates. According to an NBA source, as Wade talked, Portis stared him down.

“Wade finally says, ‘What’s up, Bobby?’ ’’ the NBA source said. “Bobby laid into him, saying, ‘You might be a better player, but don’t ever challenge my work ethic.’ He accused Wade of not working hard enough by not practicing.’’

The fire in Portis’ belly is one reason the Knicks on Sunday lavished a whopping two-year, $31 million deal on Portis with the second year a team option. That came despite Portis being a backup through much of his rookie contract.

“Bobby is truly the hardest-worker type,’’ the source said. “Not just that he says it. That’s why he got frustrated and snapped at Wade.’’

Add that Wade incident to Portis’ well-chronicled 2017 fight during practice with Nikola Mirotic and it’s clear the 24-year-old can have a temper.

Portis received an eight-game suspension and Mirotic a fractured face and concussion. They stopped speaking and Mirotic was traded three months later to New Orleans.

The two were trash-talking before and after practice when the scuffle ensued and Portis landed a blow that floored Mirotic.

“Actually Bobby’s usually a fun guy and that fight was an aberration,” the source said. “It was more Mirotic trying to show he was a tough guy in the locker room. Portis was told that day by someone the Bulls were going to make Mirotic the starter even though Bobby was beating him out. They wanted to showcase Mirotic. It was regretful. Players were a lot closer to Bobby.’’

Portis, who averaged 14.2 points and 8.1 rebounds last season for the Bulls and Wizards, was the subject of a feature by the website CloseUp360 this week centering on his crazy workouts and diet. He’s on a strict sugar-free plan, even changing his toothpaste to eliminate all traces. His 12-hour workday consists of six hours of workouts such as boxing, plus another six hours of business meetings for his various enterprises.

“I’m excited to be playing for one of the most iconic franchises in the NBA, while being able to live in one of the best cities in the world,” the Arkansas product told CloseUp360. “I’m looking forward to getting to New York and taking advantage of all the incredible opportunities the city has to offer, as I continue to build my charitable foundation and business portfolio off the court.’’

The Wizards, who traded for him last February, rescinded his qualifying offer when the Knicks offer was so high, making him an unrestricted free agent. Not considered a particularly athletic defender, he’s doing the workouts to improve on that end of the floor. He’s already become a nice-shooting big man, shooting 39 percent on 3-pointers last season. In his rookie season, Portis was a 30 percent 3-point shooter after being taken 20th in the 2015 draft.

“He couldn’t shoot at all when he came to the team and has developed a nice shot,’’ the source said. “But it’s a black hole. He rarely passes.’’

Most scouts see a backup player or marginal starter. Portis, whose goal is to be an NBA scout after retirement and who has a stake in a statistical analysis firm, has come off the bench in 200 of his 249 games. Julius Randle, also signed by the Knicks on Sunday, is slated to start at power forward with second-year man Mitchell Robinson at center.

Knicks coach David Fizdale, who is close with Wade, is said to love Portis’ passion.