Dennis Smith Jr. came to camp with a new shot — and a new body.

Smith, the Fayetteville, N.C., product with a self-admitted taste for Bojangles, took coach David Fizdale’s mandate to step up his nutrition game if he wanted to remain the team’s starting point guard.

The key piece to the Kristaps Porzingis blockbuster last January, Smith reported to training camp 15 pounds lighter and said he skipped the fried-chicken chain “most” of the summer

“Yeah, I had to change some of the things I ate,’’ Smith said. “I’m a country boy. We eat different down there. I don’t think it’s anything in particular that I cut out, it’s what I added in. I started getting these fruit smoothies, spinach and kale, I can just use that for breakfast, it’s lighter.’’

Late last season, Smith developed disk issues in his back that cost him games. Fizdale ordered him to get with the team nutritionist for a shopping spree. Smith believes the little extra weight could have caused that back pain.

“I do exercises for everything because I’m realizing how important it is, how everything’s connected — my ankle, knee, back, shoulder, wrist, everything’s connected,’’ Smith said. “So I’ve got to really be flexible everywhere I can. I lost weight. They told me to drop down so I lost a lot.

“I feel like I’ll be able to endure a long season. There’s not as much banging on my body, not as much weight.’’

Working on the mechanics of his 3-point shot with assistant coach Keith Smart was also a huge part of his summer. Smith, who was drafted by Dallas one pick after the Knicks selected Frank Ntilikina, is a career 31.6 percent 3-point shooter.

Smith has said since July he’s the X factor and could be the difference between playoffs and no playoffs.

“I’m just looking at myself as being the best version of me, doing whatever I need for this team to win,’’ Smith said. “I got to do my job and just fill a role no matter what it is.’’

But he added, “I feel good [with my shot]. I’m going to put ’em up.’’

Center Mitchell Robinson continued flinging 3-pointers at the end of practice Tuesday. The shot-blocking menace attempted just three jump shots all last season.

“I didn’t practice it not to use it,’’ Robinson said.

Fizdale sounded excited.

“He’s a really good free-throw shooter for a big, so he’s got a nice touch and shooting stroke,’’ Fizdale said. “The coaches have done a really nice job of working with him. I think you’ve seen when he’s out there shooting the ball goes in a lot for a big 7-foot guy. But at the same time we’re not neglecting what he needs to do.”

Fizdale repeated the offense will be more complex than last season’s heavy iso and straight pick-and-roll sets. Fizdale indicated the league’s youngest team couldn’t handle more.

“Way more diversity in the offense,’’ he said. “More screen-aways, more cross-screens, different motion movements, because, again, we got a lot of different pieces now. I want everyone to feel actively involved in the offense.”