Nick Schmaltz was munching on a greasy, limp slice of Little Caesars pizza Friday night in the visitors’ dressing room at Joe Louis Arena as he dissected what went wrong in a 4-2 loss to the Red Wings.

In the moments after an NHL game, there are no dietary restrictions, no concerns about organic food and lean proteins. There’s pizza in a lot of cities, or chicken wings in Buffalo or even poutine at some Canadian rinks. After expending all those calories on the ice, an NHL player after a game could probably digest a puck without much difficulty.

But postgame is the exception. Every other day and every other meal, hockey players are becoming increasingly fanatical about proper nutrition, about monitoring everything that goes in their bodies, about maximizing their physical potential. And the three Blackhawks rookies are fully on board as they make their way through their first full NHL season, a grind the likes of which they’ve never known.

“I wasn’t big into it before I came here, but you learn quickly how you’ve got to take care of your body and what you’re putting into it,” Schmaltz said. “In college, it was always Taco Bell or whatever you can find.”

The indefatigable Duncan Keith is the model for what proper nutrition can do for an athlete, and the meticulous Jonathan Toews is the evangelist, preaching the benefits to anyone who’ll listen, rookie or veteran. But the Hawks as a whole take nutrition seriously. During Ryan Hartman’s first season in Rockford, the team had a nutritionist take him and a bunch of other first-year pros on a field trip to the grocery store for some remedial food training.

This is a vegetable. Vegetables are good. You should eat them.

They even send players to a cooking class to show them how to make a proper meal — organic food only, lean proteins, lighter carbs such as sweet potatoes. Hartman started taking it seriously this past summer, knowing he had a real chance of sticking in the NHL. And as he approaches a career high in games and faces down a frenetic stretch run and a potentially long postseason, he’s reaping the rewards.

“If you don’t want to do it, you’re not going to do it,” Hartman said. “But they give you the tools to do it. It can’t hurt. Obviously, you see how it helps guys like Toews and Keith.”

Tanner Kero has always had a more restrictive diet, which always meant he was the weird one in college. When he and his buddies at Michigan Tech would go out to grab a bite to eat, he’d be the one ordering a salad amid all the greasy burgers and pizza. When he turned pro at the end of the 2014-15 season, he was excited to find kindred spirits among his teammates.

“It’s kind of nice when more of the guys are focused on it, so you don’t feel like the outsider, worrying about getting a salad with every meal,” Kero said. “Everyone’s a little more focused on it here.”

The team provides many of the meals, particularly before and after practices and on the road. After games, players are chugging all sorts of protein shakes and thick, gruel-like substances to help them recover faster. It’s a far cry from coach Joel Quenneville’s playing days, when postgame recovery came with a pull tab.

“Night and day,” Quenneville said. “Definitely a big difference in how they manage their lifestyle and how they prioritize what goes in [their bodies], how they sleep, how they train and how they prepare. The commitment is around the clock. Their drinks are a little different than beer.”

That’s not to say life is an endless drudgery of bison, grilled chicken and sweet potatoes. There are still those sinful postgame gut bombs. And, yes, maybe the occasional trip to a fast-food joint. Just as long as it’s on a night off. With no game the next day. And then it’s probably straight to the gym afterward.

“Every now and then, you’ve got to treat yourself,” Schmaltz said. “I still go to Taco Bell sometimes — just not every other day like in college.”

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Email: mlazerus@suntimes.com