These guys went from having “dad bods” to rocking rad bods.

Coined by a college student in 2015 and embodied by a shirtless Leo DiCaprio (who’s not a dad at all) frolicking on a beach with a pint-sized paunch hanging over his board shorts, a “dad bod” has come to signify the physique of a middle-aged man who’s just slightly let himself go.

But for these three fathers, being an average Joe with a dad bod had its drawbacks — low energy, bad moods and the feeling that they’re missing out on quality time with their children. “I realized I needed to be around for my son, and I wasn’t doing a good job taking care of myself,” says David Corcoran, a dad who’s shed more than 70 pounds.

So, for their kids, their bodies and their mental health, they ditched the doughnuts and lost the weight. Here’s how they did it.

The Vegan Warrior

David Corcoran, 35, Stamford, Conn.

Before: 252 pounds

After: 175 pounds

In the summer of 2017, Corcoran, 35, was on vacation with his wife in North Carolina’s Outer Banks when he saw some “muscular-looking” men walk by. “I look like that, right?” he asked his wife. “Um, sure?” she replied.

Corcoran, an accountant at an asset-management firm, says he was going to the gym frequently and lifting weights but didn’t have any sort of fitness plan. He really did think his 6-foot-2 frame was muscular like the guys on the beach, albeit a tad less ripped, despite eating his office’s catered lunches — pasta, sandwiches, pizza Fridays — daily with “no regrets.”

After the summer trip, he got a scale, and was shocked to see he weighed more than 250 pounds.

“I started looking at my life. [I was] overweight, on medication for high blood pressure, [had] high cholesterol, a stressful job [and] a history of heart disease in my family,” Corcoran recalls.

Corcoran decided to take up running, but didn’t make weight loss a real priority until Christmas 2018. He’d lace up his sneakers and hit the pavement for at least 25 to 40 minutes daily, working his way up to 6 miles a day. He also started lifting free weights for at least 30 to 40 minutes a day.

“I remember by [spring of] 2019, I had dropped down to 195 pounds,” Corcoran says. “I was so happy to go to my doctor for my six-month blood-pressure checkup, but my doctor said it was still too high.”

That’s when Corcoran decided to “take it to a whole different level,” he says.

“I told my doctor that I was going to run my blood pressure down,” Corcoran says. “I started doing 10-mile runs. I also completely overhauled my diet.”

Corcoran started with some intermittent fasting, skipping breakfast and cutting out sugars and refined carbs. By the fall, he decided to go vegan.

“I eat an avocado a day,” says Corcoran, either sliced on toast, diced over quinoa, or over Just Egg (a vegan substitute brand). “I eat a ton of fruits and veggies. I cut pasta and bread, originally, although I do eat some bread now. I eat two meals a day: basically a big grain bowl with a lot of veggies and a big salad with nuts and beans.”

By the end of October 2019, it was time for Corcoran’s annual physical.

“I was ready,” Corcoran says. “I felt invigorated, like everything was just working better. I felt more alive and more energetic. I had a lot more confidence.”

That’s when he got the best medical news of his life: His blood pressure was the lowest it had ever been and his cholesterol was perfect.

“My doctor was impressed with my transformation. I’m off my medication,” he says. “Changing my diet changed my life, even more than exercising.”

Corcoran has maintained his current weight loss for more than six months and says he is very comfortable with his current lifestyle, which includes quitting booze this past January.

“I went through this phase where I was posting a lot of shirtless pics,” Corcoran says. “It’s shocking to have a six-pack for the first time in my life at 35 years old. It’s empowering. I feel like I can do anything.”

Corcoran’s top tips:

You have the time

“I did all of this while also working 60-hour weeks,” Corcoran says. “The easiest way to find the time is to wake up earlier then you normally would. On weekends, I’ll wait for nap time and alternate with my wife. It’s easier to make excuses to avoid the gym after work than in the mornings.”

Switch it up

Corcoran has experimented with a lot of different diets over the course of his journey, such as intermittent fasting, before going vegan in October. “Since I switched [to veganism], I feel so good,” he says. “Not that it hasn’t been difficult. My last night of [eating meat] I went to Dinosaur Bar-B-Que and spent like $100 on a ‘last meal.’ ”

The No-fuss Faster

Jay Dacanay, 43, Essex County, NJ

Before: 250 pounds

After: 176 pounds

After 12 years in the Army, father of two Jay Dacanay, 43, joined the corporate workforce as an onboarding analyst at a bank downtown and watched his kids — and his gut — grow and grow.

“My weight gain happened over 10 or so years,” Dacanay, who is 5-foot-7, tells The Post. “Every year, I’d gain three pounds and the scale just got higher and higher. I’m a traditional dad. I’m up early, go into the city for work, and come home and want to spend as much time as possible with my kids. Exercise never really fit into that.”

Bagel breakfasts, cookies and cupcakes in the office, sandwiches, and even a whole pizza would be a typical day’s meals. He’d snack on bread while waiting on line to order macarons at the French bakeries near his office.

“I just really love pizza, meatball subs, hero sandwiches, cookies the size of my face,” Dacanay says. “I would call myself the Filipino Joey Tribbiani. I really thought that since I was never overweight by Army standards and could always, even at my heaviest, bang out 75 pushups without a problem or run 2 miles, that I was OK.”

It wasn’t until Dacanay was more winded than usual in his family’s big Thanksgiving 2017 football game (“We have a trophy and everything,” he says) that he decided to make a change.

“I jumped on the scale the next morning on Black Friday, and was like, ‘Are you kidding me?’ ” he says. The scale read 250 pounds.

Dacanay spent the rest of the holiday season doing “the typical eat-less, exercise-more” diet and by Christmas, he has lost a little more than 10 pounds. Still, it wasn’t enough.

“I was always mad. I hated my life. [I was] just not happy in my own body,” Dacanay says. “My kids thought I was mean — that Army man who babysat terrorists in Guantanamo Bay after 9/11, but my wife knew better, she knew the real me. She said, ‘Instead of being a jerk, why don’t you be the happier guy you were before. You snap at people. You’re snapping at the kids. That’s not cool.’ And she was right.”

Around the new year, Dacanay downloaded an app from Al Kavadlo, a Brooklyn-based bodyweight strength-training and calisthenics expert.

“I love it,” Dacanay says. “You don’t need any special equipment. I could work out at home. Pushups, situps, cardio, HIIT [high-intensity interval training], planks. Eventually, I installed a pullup bar; that’s the only equipment. I could be at home with my family but still get a workout in.”

Next, Dacanay overhauled his diet, changing how — and when — he eats.

“I started learning about intermittent fasting and at first, did a standard 16-hours-fasting, eight-hours-fed program for a while,” he says. “A few months later, I was walking around with my shirt off all the time.”

By the summer of 2018, the regimented eating routine helped Dacanay get down to around 170 pounds. Today, he’s maintained that weight loss for a year and a half and is still actively doing intermittent fasting — even dabbling with an extreme version of the diet, known as OMAD (one meal a day), although he will allow himself treats like bubble tea with his family. He also tries to work out three to five days a week (a mix of HIIT, power yoga and calisthenics).

But even though his approach seems intense, it was just what this Army vet needed to stay on track.

“Every aspect of my life is better now,” he says. “I have more energy, my mood has improved, my skin has cleared up. I feel like I just added a decade to my life.”

Dacanay’s top tips:

Find your why

“My ‘why’ is my wife and kids,” he says. “Find a strong ‘why’ so when your mind goes to a bad decision, you can remember why you’re doing it all in the first place.”

Reward yourself

“I used to be more strict, but I’ve found if I stay away from processed foods and refined carbohydrates, I can have a cookie at a kid’s birthday party and it’s OK,” he says.

The Reformed Overeater

Rocky Parejo, 40, Toronto

Before: 189 pounds

After: 145 pounds

At 189 pounds, Rocky Parejo was never considered “fat.” But he was far from fit.

“It was all uncomfortable belly fat,” Parejo, 40, tells The Post. “Gross, weird-looking belly fat. Skinny arms, skinny legs and a huge belly.”

He worked as a chef for 17 years, and only cared about flavor, not calories. “I had no sense of portion control back then,” he says.

A typical breakfast would include three pieces of toast, three eggs, a coffee and even maybe a cookie. Lunch usually happened while at work in the kitchen, where he’d snack on chicken, rice and french fries. Dinner was always late — “like an hour and a half before I went to sleep,” he says — and would consist of pasta with alfredo sauce or a heavy beef stew. He estimates that he’d down about 10 beers a week.

“I’d eat half a bag of Oreos for dessert,” the 5-foot-7 Parejo says. “I had an endless stomach . . . salty chips and anything with chocolate.”

Before long, Parejo was having trouble playing pickup baseball and basketball. But it was the birth of his daughter — when he was 38 — that gave him the real motivation he needed to create a new life.

“I realized I wanted to be able to keep up with my child,” Parejo says. “She’ll be in her 20s, and I’ll be in my 60s. I wanted to be there to scare off her future boyfriends.”

So Parejo started Googling everything he could on how to lose belly fat. He joined a gym and made simple changes to his diet, such as adding greens to meals — he’d make one-pot dishes and add “loads of greens like kale or Swiss chard.” Still, he regretted spending so much time away from his fiancée while he was working out.

“It felt weird for me, like, ‘Oh, I’m going to the gym, babe, you take care of the crying baby,’” he says.

So, he decided to make health his career. In December 2017, he quit his job cooking at an Italian restaurant, put the $700 fee for fitness certifications on a credit card, and signed up to be a trainer.

“Everyone thought I was crazy, starting over completely,” Parejo says. “But I knew I had the enthusiasm and motivation to do it.”

After completing his training, he still felt self-conscious about his mid-section, and was dismayed at being initially rejected for jobs. But after being hired at an F45 location in Toronto, a gym that specializes in cardio and resistance group training, Parejo “went to work.”

He gets up at 2:30 a.m. and is in the gym by 3:30 to work out at least five times a week “without fail,” he says — a mix of cardio and strength training incorporating high knees, burpees, kettlebell swings, calisthenics, bodyweight exercises and more. Despite sounding insane, his routine is coincidentally on par with Mark Wahlberg’s early morning habit, another F45 fan. He eats salads, veggie bowls and, if he eats grains, it’s always quinoa or couscous, never white bread or pasta. In fact, he cut pretty much all refined carbs out of his diet in August 2019.

He’s managed to keep off 44 pounds for about a year, and his abs are getting more ripped every day.

“My wife says that she never thought my body would look like this,” Parejo says. “She makes a lot of comments about my abs like, ‘Babe, I’ve got some clothes to wash, can I use your abs?’ ”

Parejo’s top tips:

Start your day strong

Parejo starts his day with 2 tablespoons of apple cider vinegar mixed with 1/4 cup of warm water because, he says, it suppresses his appetite, then dives into a bowl (or thermos) of oatmeal. “I eat oatmeal almost every day,” Parejo says. “It’s filled with fiber and it gives me the energy I need.”

Stop eating at least three hours before bed

“This simple trick really helped to jump-start my weight loss, before I spent any time in the gym at all,” he says.