Patty Pena has struggled with her weight since she was in elementary school.
The 40-year-old administrator at Chicago Bulls College Prep, an inner-city charter school in Chicago, said when she was a child, her mother would have to buy her clothes in the women’s section of department stores.
She gained even more weight in college, and ended up weighing 252 pounds.
A member of what she calls “the clean plate club,” the mother of two would often eat more than her own dinner.
“If my kids had food leftover … I'd say, ‘Well, why am I going to throw that out? It’s perfectly fine,’” she said.
Pena told “Good Morning America” she knew she had to take charge when her school introduced a fitness initiative to help students get healthy.
“I said I can't have them … need some support from me and me not be able to give that to them, because I myself was so overweight so I said, I have to do it,” she said.
Her story, and the stories of others who’ve also shed a lot of weight, is detailed in People magazine's annual "Half their Size" edition, which is out on newsstands today.
Pena worked out, starting off slowly and realistically and finding activities that she liked. Before she started losing the weight her mobility was limited, so she would walk in place, do squats and run in place all while watching her favorite TV shows. She joined Weight Watchers to modify her diet.
Pena also joined a gym, but said she found the environment there so judgmental that after one class she cried in her car.
That’s when she decided to work out with the students at her school during their physical education classes.
Pena lost 132 pounds, and now tips the scale at 120.
For Carlos Romero of Seattle, food was a source of comfort. His weight ballooned to 437 pounds.
“I was always overeating,” the 31-year-old told “GMA.
It wasn’t until Romero, an operations analyst, was diagnosed with facioscapulohumeral muscular dystrophy – a disease that causes progressive skeletal muscle weakness – that he decided to turn his life around.
“I saw it as an opportunity to inspire people that were struggling with obesity … and muscular dystrophy,” he said of the diagnosis he received two years ago.
Romero has since become a para-athlete. He does cardio and resistance training three times per week, and goes climbing up to six times per week.
"We're actually making progress towards the first treatments," Romero said.
During their appearance on “GMA” today, Romero and Pena talked about how they maintained their commitment to their new lifestyles during the holidays, when they’re surrounded by family and lot of food.
Romero recommended that people hit the gym before a big holiday meal, rather than afterward.
"I think it's really easy for people to promise themselves that they're going to work off those calories afterwards but it usually doesn't happen, so I believe in getting the work done first, before you reward yourself," Romero said.
Romero suggested that families have a fun Zumba or class or dance party after a big holiday dinner.
"We get moving in our house," Romero said. "We put on some music and we have a Zumba party or we just get out of our chairs and we just walk around."
"We enjoy each other's company a lot more," she said.