ATLANTIC CITY — Bryant Jennings' headline fight against Alexander Dimitrenko at the Ocean Resort Casino on Saturday night marks the Philadelphia-born heavyweight's biggest challenge in three years.

A lot has changed for Jennings in that time.

In 2015, Jennings transitioned from being vegetarian, a diet he had followed for two years, to being vegan. That same year, Jennings also lost his undefeated record and saw his push for numerous world titles derailed by consecutive losses to Wladimir Klitschko and Luis Ortiz.

Jennings (23-2, 13 knockouts) has won a series of relatively low-difficulty fights since then, including most recently against fellow Philadelphian Joey Dawejko at the Liacouras Center in April. He hasn't faced anyone like Dimitrenko (41-3, 26 KOs), who has a long track record of success and four inches on the 6-foot-3 Jennings.

"He's a tall guy, bigger guy, well experienced, pretty crafty," Jennings said of the Russia-born fighter. "He'll be a good challenge for me."

Jennings doesn't claim that being vegan makes him a better fighter on a day-to-day basis — "If there was one thing that you could do that would change you next week, I think everybody would be doing it," he said — but he hopes the lifestyle change will allow him to extend his career longer than most.

"Being vegan and changing your diet and focusing on your health is a more long-term thing," he said. "It's definitely kept me feeling young, looking young, recovering absolutely phenomenally, but the long-term effects I really look forward to."

Given that he'll turn 34 next month, "long term" is not too far away. In the meantime, though, Jennings said he no longer deals with cramps or charley horses and recovers more quickly after tough workouts, benefits he attributes to hydration and eating vegetables and starches almost exclusively.

While many vegans simply replace meat with a meat substitute, such as tofu, tempeh or a synthetic meat product, Jennings does not.

"It comes from the vegetables. Every animal that we eat is a herbivore, and they get their protein from the plants," he said. "I'm not a big protein supplement-type guy. … [It's about] just completely blocking that out of your mind and saying, 'OK, my whole meal consists of all vegetables.'"

At a training session Wednesday, Jennings stayed in the locker room throughout Dimitrenko's allotted time in the ring, emerging only for his own shadow-boxing segment once his opponent had left. He said he will prioritize getting comfortable within the first three rounds of Saturday's fight, citing comfortability as a frequent challenge for him.

But as far as what he'll bring to the showdown, Jennings was not shy to boast a little.

"My strengths are just being very absorbent, quick-processing, very durable," he said. "I have a well-rounded quality of attributes to bring to fights."

Jennings vs. Dimitrenko

Where: Ovation Hall at Ocean Resort Casino, Atlantic City.

When: Saturday, 10 p.m.

How to watch: ESPN.

Co-feature: Jesse Hart vs. Mike Gavronski (super middleweights).