Two years ago in April, Ali McCarthy agreed to go to a Weight Watchers meeting with her stepmother.

On a Sunday this spring, she drove into the parking lot of the Weight Watchers Center on Running Hill Road in South Portland nearly 120 pounds lighter than when she joined.

The 37-year-old from Westbrook missed a few times, but never because she didn’t feel like it or was scared of what the scale would say.

“I’ve had people come up or gone away for the weekend,” McCarthy said.

The support she found and the friends she made kept her coming back, gain or loss.

After losing 5 pounds the previous week and 3 pounds the week before, she was expecting a gain this Sunday. She’d learned that’s how it works. Still, she hoped for the best.

When McCarthy got on the scale before the first meeting, she weighed in at 335 pounds – less than she feared, but more than she ever wanted to admit.

“On my license it says 280 or something, because that’s as far as my mind wanted to go,” she said.

A skinny kid whose grandmother used to tease her about needing to drink a milkshake, McCarthy filled out when she hit puberty and, though she felt heavy in high school, was a fairly healthy weight for her 5-foot-4-inch frame – 150 pounds. That’s now her target.

Like a lot of people, McCarthy put on weight in college, but it wasn’t until her junior year that it started to become unmanageable.

She was living with her parents in Westbrook and about to start classes again at the University of Southern Maine, when her mother – who had Type I diabetes – went into the hospital for her second leg amputation.

Something went wrong during the surgery and she ended up on life support. McCarthy’s family was facing the decision of whether to take her off of it, when suddenly there was no longer a choice.

McCarthy barely remembers that day or the year that followed her mother’s death.

“I kind of sailed through it,” she said. “I kind of threw it in the back of my head and kind of ate it away.”

• • • • •

School was a welcome distraction and she kept going until she earned a bachelor’s degree in history – a subject for which she and her mom shared a love.

After graduation, she did temp jobs and data entry before deciding she wanted to try something new in a warmer climate and moved to Orlando, Florida. Within a year, McCarthy ended up missing her family, and even the weather, and moved back. Unhappy with where she was in life, her weight continued to climb.

She got a paralegal certificate from Andover College and a job at a bank before landing work at a law firm, but was later laid off. A temp agency placed her at Guiding Stars Licensing Co., a company in Scarborough that rates the nutritional value of items sold at Hannaford Supermarkets.

Although she spent her days entering nutritional information from food containers and assigning a certain number of stars based on healthiness, she didn’t apply that knowledge to her own diet.

A typical dinner was four servings of spaghetti or a frozen pizza followed by mindless handfuls of milk chocolate candy while watching Netflix from her recliner.

“I’d just eat and eat and eat,” she said.

A few times a week, when even those meals seemed too much to make, there were the trips for fast-food, loaded burritos or double quarter-pounders with super-sized fries.

“Everything was big. It was never small,” she said. “I feel like I was on empty 98 percent of the time.”

She tried Weight Watchers and a few fad diets, but whatever she lost she always gained back.

• • • • •

The latest attempt started like any other. The day of her first Weight Watchers meeting, McCarthy cleared the junk food from the pantry and refrigerator of her third-floor apartment on Bridge Street and went grocery shopping for healthier replacements.

That night, she made a chicken and cheese casserole from a recipe that her stepmother found online.

The first week she lost 8 pounds – providing enough motivation to keep going the next week, and that was all she worried about.

She made small goals for herself, 5 pounds at a time, and tried not to think about how much she had to lose altogether.

“Before, I was so focused on the big number that I would just get overwhelmed with it and quit,” she said.

McCarthy made it six months when a doctor’s appointment gave her another reason to keep going. She found out she was pre-diabetic.

Hearing the word brought back the devastation of losing her mother and a drive to avoid becoming a victim of the same disease. Losing weight was imperative.

For the first year, she kept her focus on food, keeping track of what she ate and not letting slip-ups derail her.

She started cooking more and paying attention to portion size, using a scale to measure out ingredients. She learned to make a healthy version of macaroni and cheese and a baked chicken dish that she loves.

She didn’t stop eating all the things she used to, she just ate less of it. Frozen pizzas are still lined up in her fridge, but they’re a fraction of the size.

A year into the program, McCarthy added exercise to her plan. She joined a water aerobics class at Westbrook Community Center. Friends she had made at Weight Watchers invited her to walk Back Cove in Portland with them, which she does twice a week.

They started emailing every day, too, checking in and keeping each other accountable. When McCarthy recently ate a Milky Way out of stress, she admitted it to them right away.

One weigh-in in January, she surpassed the 100-pound mark. The woman behind her in line started screaming, but for McCarthy it only felt like “a speed bump,” she said.

• • • • •

Although the achievement came with a medallion that she wears around her neck and a certificate that hangs on the wood-paneled wall by her recliner, at the time it was just another week – the same way she looks at the weigh-ins that don’t go so well.

“Your body goes through like this,” she said, making waves with her hand to mimic the ups and downs of weight loss. “You’ve just got to expect that, and that’s where a lot of people get frustrated.”

Losing 100 pounds, however, did inspire McCarthy to step up her exercise, and her weekly routine is now as ingrained as her old habits once were.

Every weekday, she leaves her apartment before 5 a.m. to get in a hour of walking on a treadmill at her office gym before work at Guiding Stars, where she’s now a full-time employee. On Mondays and Wednesdays, she walks with her Weight Watchers friends. Tuesdays and Thursdays are Zumba classes at the community center.

“My dad said to me the other day that I’m never home,” she said. “It used to be you could find me in that chair 98 percent of the time.”

On Saturdays, McCarthy takes a walk around her neighborhood when she gets up, then plans out what food she needs to buy on her weekly shopping trip Sunday right after Weight Watchers, where she arrives for her weigh-in at 8 a.m.

That Sunday this spring, she was managing her expectations when she walked into the weight-loss center in pink sweatpants and a T-shirt.

“I get anxiety right before, because I want to lose,” she said about her weekly weigh-in. “If I don’t, I try to accept it.”

Standing in line, she was handed a pamphlet with new recipes and the theme for the week: “Get happy.”

Flipping through the pages, she made her way around the stanchions and, when it was her turn, stepped up to a station at the counter where a gray scale with no numbers sat on the floor.

She handed a woman her weigh-in booklet, slipped off her flip-flops and stepped on the scale.

Behind the counter, numbers appeared on a digital display. She was up 1.3 pounds from the last week.

“I figured,” McCarthy said, then put on her sandals, took her booklet and walked into the meeting room, where she sat in the same spot she had the week before and would the week after.