Time doesn’t seem to be slowing Marcus Davis. It certainly isn’t weighing on him.

A slimmer, lighter Davis will be back in the octagon New Year’s Day to prove that experience and maturity can still triumph over youthful energy, even in a young man’s sport like UFC (Ultimate Fighting Championship) mixed-martial arts fighting.

The 37-year-old longtime Bangor resident and Houlton native will be fighting his first UFC bout as a lightweight Saturday in Las Vegas after shedding 55 pounds from his top weight and 15 pounds from his normal fight weight as a welterweight.

“The last time I fought at 155 may have been 2005. I decided to drop to fight for a mixed-martial arts title fight,” said Davis, who will take on Jeremy Stephens in one of three UFC 125 undercard bouts televised live nationwide on the Ion Network. “That was the last fight I did before going on the show.”

“The show” was The Ultimate Fighter, which propelled Davis into the limelight and earned him a UFC contract.

Thirty fights and five years later, Davis hopes to have finally seized on the perfect training regimen, weight and diet to propel him into the upper echelon of pro MMA fighters.

Currently, Davis has no UFC lightweight ranking, but one MMA website and ranking service ranked him 43rd among 44 welterweights. Another had him 16th. Stephens is presently listed as 24th out of 38 lightweights by one site and 14th by another.

“We’re both hard punchers with great chins. I think he fights with way more emotion than I do. He comes right at you,” Davis said.  “I think he’s going to come out and throw hard punches and kicks and try to knock me out. My preference would be to slowly, methodically pick him apart piece by piece, round by round, and knock him out.”

Davis, who’s 22-8 overall in MMA, is the underdog according to four different UFC betting line services, but that’s fine with him. He thinks he has newfound advantages in this fight.

“I think I’ll be more comfortable at this weight, and my body’s already adjusted,” said the 5-foot-10 Davis.

The 24-year-old Stephens (18-6) is 5-foot-9 and listed on his UFC profile as a fighter with a lot of heart and “heavy hands.” This is the 11th UFC fight for the Iowa native.

“I felt like all the fights I’ve had before that I was in a young man’s game and just trying to survive and get to the next fight,” said Davis. “This is the first fight I’m going into totally healthy. I’m going in to fight, have fun, and enjoy myself.”

This is the 16th UFC fight for Davis, who says the last time he felt totally healthy and pain-free was against Paul Taylor in September, 2007 (Davis won by submission in the first round).

Davis credits Dr. Gary Ross of Brewer Health Center for the turnaround in his health.

“The health problems for me really started two years ago and it kept getting worse and worse. I was having impingement syndrome and pain in my shoulders and right leg,” Davis explained.

Davis says Ross helped him identify the causes, not just symptoms, of his ailments. He had three bulging discs in his neck and a fourth starting to do the same that were largely causing the shoulder and leg pain. In addition to having two epidural injections to shrink the discs, he also had to radically alter his diet and exercise regimen.

“I had to learn to include some things I was lacking like vitamin deficiencies, my diet, allergies to certain foods,” said Davis. “I think I’ve been pain-free since about the end of September.”

Davis avoids all foods made with rice, flours, gluten and refined sugar. He also shuns processed foods.

“I combine Green Magma and LifeForce and drink a liter every morning with stuff like alfalfa sprouts, blue algae, green algae, barley, wheat grass, and other sprouts in it,” he explained. “I also drink lots of Alive shakes (living organism food shakes high in chlorophyl) and I eat a lot of raw almonds, nonfat cottage cheese, wasabi peas, Greek yogurt and Kashi.”

The holiday season was admittedly tough for Davis, but he plans to make up for all the treats he avoided.

“My wife made about 10 different kinds of cookies and I couldn’t have a single one, but I’m going to break my diet right after the fight because she’ll have a platter of cookies in the back seat when she picks me up from the airport Sunday night.”

Davis and trainer Garth Krane also have added a lot of cardiovascular exercises and drills to his training.

Davis’ fight is one of three scheduled to air live, 9-10 p.m., on Ion, which is available in 100 million homes nationwide on Dish Network, DirecTV, and regional cable systems like Time Warner (channel 12 in greater Bangor).