Kristen McLaughlin was an active kid. She played three sports throughout high school, which helped her “balance out my eating.” But that all changed when she “became sedentary” in college — and found herself stuck in a complicated, 5-year relationship.

“I wasn’t mindful at all about what I was eating,” McLaughlin, 31, tells PEOPLE for the 2019 “How I Lost 100 Lbs.!” feature. “If I wanted to eat something, I didn’t really think twice about it. And when I got into my relationship, he was a larger guy, and I was eating whatever he’s eating — which does not make logical sense.”

The New York City-based software specialist says she was an “emotional eater,” and together she and her boyfriend would regularly treat themselves with dinners out — for happy or sad moments.

“It was easier for me to eat instead of tackling what was going on,” she says. “It was easier to say, ‘I’ll feel better for 15 minutes while I’m eating a cheeseburger’ and not think about how bad I would feel afterwards.”

McLaughlin would typically skip breakfast or get a chocolate croissant, and then “treat” herself with a big taco bowl for lunch to make up for the missed meal. For dinner with her boyfriend, “we would order giant pizzas or cheeseburgers and French fries,” and if they went out for drinks, “you deserve to have something when you come back home” to soak up the alcohol.

“I would fall asleep with probably 12,000 calories in me, and then wake up and wonder, ‘Why am I so tired?’ ” she recalls.

At 270 lbs., McLaughlin felt self-conscious about her body and that she was “comparable” in size to her boyfriend. In 2016 decided to join Jenny Craig, and the meal plan worked — she lost about 60 lbs. — but she felt bad about having ready made meals while her boyfriend, who was getting his M.B.A at the time, had to “fend for himself” in the kitchen.

“I had some guilt about losing the weight while he had school going on, and I wanted us to spend more time together,” she says. “So I lost a bunch of weight but then slid back.”

Around the same time, McLaughlin’s boyfriend became “distant,” and didn’t always come home after work. She learned that he had feelings for someone else.

“At that point I’m like, ‘This is cheating, this is dumb, I can’t do this anymore,’ and I said I was leaving,” she says.

Looking back, McLaughlin says it was the “best thing” that could’ve happened to her, although at the time she felt overwhelmed by the loss of her 5-year relationship and the sudden need to find a new apartment.

But she also saw it as a clean slate. “I literally got rid of every excuse that I’ve ever had,” she says. “I never had a better opportunity to just focus on myself and build myself back up.”

McLaughlin returned to Jenny Craig in Feb. 2017 and set her sights on losing 100 lbs. in a year. This time it stuck — for good. She would eat the prepared meals each day with grilled vegetables on the side, and then walk home from work every evening. The weight steadily came off, and she soon discovered an interest in workout classes and weight training.

A year later, in Feb. 2018, she was down 100 lbs. and celebrated with a vacation in Cancun. McLaughlin has since lost even more weight — she’s nearly at half her size, having lost 133 lbs. — and now knows the right portions and foods to eat to maintain her weight loss on her own. McLaughlin says it has changed her life.

“I think I’m more myself now, funnily enough, than I ever was the previous 30 years,” she says. “I say yes to things now, I’m more outgoing, I’m more likely to be social. I think weight loss isn’t just physical or mental — it’s a whole spectrum of your life.”