WORCESTER, Mass. — In the red corner, standing 5-foot-7-inches tall and weighing 140 pounds, “the evil twin,” Kerri Lewis. And, in the blue corner, standing 5-foot-8-inches tall and weighing 145 pounds, Kerri’s twin sister, Ellyn Guinding.

Kerri Lewis and Ellyn Guinding have a lot in common. They are fraternal twin sisters. They are the same age, 31, but Lewis is 7 minutes older. They are both Worcester natives. They both work for a living. Lewis is the manager at Starbucks in Auburn, while Guinding is a nurse, a waitress and a U.S. Army reservist who is being deployed in September.

The sisters are also happily married. Each has two children. They are best of friends.

Still, Lewis confesses that sometimes when she looks at her twin sister lately, all she can think about is where she can throw a punch. That doesn’t bother Guinding, because, at any given moment, she’s probably thinking the same thing. The sisters will face each other in the boxing ring for what promises to be a no-holds-barred, slugfest on May 3 at the Worcester Palladium. The bout will be part of the annual “Give Kids A Fightin’ Chance” charity boxing event to benefit the Boys and Girls Club of Worcester.

Lewis and Guinding are part of a rising trend — women choosing the male-dominated sport of boxing as a means of getting in shape and shedding pounds.

Female boxing is so popular that 24 women were scheduled to compete in the women’s U.S. Boxing Olympic Trials in Washington State. This summer, for the first time, women’s boxing will be included in the Olympic Games.

Lisa Creech Bledsoe of Raleigh, N.C., started boxing for fitness four years ago when she was 42. Three years later, she became a competitive amateur boxer. Her insights on boxing, including her “13 Reasons Why Women Should Take Up Boxing,” can be found on her website, www.theglowingedge.com .

“I can tell you why every women is attracted to boxing for fitness,” Bledsoe said. “It burns 1,000 calories an hour. Every woman in the world wants to know about that.

“Competitive-wise, it’s a great mountain that you have to climb,” Bledsoe said. “There’s a lot of fear and anxiety involved in getting ready for a fight but the fight itself, or even just sparring, is a huge rush. And it makes you want to do it again.”

Freddie Potenti, the nephew of former New England welterweight champion Johnny Potenti of Worcester, is a boxing trainer at Camp Get Right, 55 Millbrook St., Worcester. He said a lot more women than ever have been taking up boxing training.

“Boxing is one of the best all-around training that you can do for any sport. It’s great for weight loss and it’s not boring,” Potenti said. “Running on treadmills and stuff, that’s all well and good, but it’s very monotonous. Boxing is a way for them to lose pounds, tone up, get in shape and have fun doing it.”

Carlos Garcia, the senior boxing instructor at the Boys and Girls Club of Worcester, has been training the twin sisters for their May boxing match. He said he has noticed that more females are getting into boxing for fitness.

“In boxing, people can lose weight easy,” Garcia said. “And, not only that, they can get in top condition right away.”

Lewis weighed 185 pounds after giving birth to her second child, Billie, who is now 2. So she decided she wanted to lose “the baby fat.”

When they wanted to shed a few pounds, the two, fist-swinging sisters never thought about skipping rope, doing neighborhood strolls and taking an aerobics class to get in shape.

“That’s too stereotypical for me. That’s just putting us women into a box,” Guinding said.

“I like the fact that boxing is a sport where body image is not a necessity,” Lewis added. “I think that too often young women are forced to be confined into this certain mold. They have to be really, really thin and can’t have muscles. That, to me, is not the way I want to teach my daughters. I took up boxing, really, because I thought it was cool.”

Neither of the sisters was an athlete until age 30, when Lewis started boxing and Guinding joined the U.S. Army. She started boxing just two weeks ago. During their formative years, rather than playing sports, both hung out and partied, the women said.

“When I was a teenager, I was a little wild child,” Lewis confessed. “I was not a straight As student and I definitely had my share of trouble.”

“We were both fighters in high school,” Guinding added. “We used to get into fist fights with people.”

When asked if they pack a mean punch, Guinding answered, “I think I do,” while her older sister confidently replied, “I know I do.” However, Guinding countered, “I beat up her ex-boyfriend,” with beaming pride.

The sisters agree that a big misconception exists on how aggressive women can be in the ring.

“Certain people think guys are rough and tough and fight it out,” Lewis said. “But, women in the ring, it’s a dogfight.”

“I think women are more aggressive,” Guinding added, “because we have more to prove.”

Both women concur that boxing is a self-esteem booster, stress-reliever and an addictive adrenaline rush. “I eat seven times a day. In the morning, I eat five to six egg whites with a bowl of oatmeal and berries and then every two hours after I eat a small meal, whether it’s a protein shake or lean meat with vegetables,” Lewis said. “I do Bikram yoga five times a week. I try to train six days a week.”

“I eat hamburgers and French fries,” Guinding said.

While they love how their bodies look and feel since they have taken up boxing, there is the small matter of the fight in a few months.

“Our mother is mortified,” Guinding said. “Everybody’s like, ‘That’s your (expletive) sister! How can you do that?’”

“We’re best friends. I’m so confident about our relationship,” Lewis added. “And, honestly, what really drove us to do it is what person wouldn’t pay to see two twins fight each other? Absolutely.”

For the record, Kim Daniel, the twins’ mother, is picking Guinding, who has a longer punch, to win. However, for the sisters, the fight is too close to call.

“We are both very strong and empowering women,” Guinding said. “And it’s a good model for our children to see us do things that are not the girlie-girl-type of thing.”