One day in 2017, Martha Elizondo found herself in the scale aisle at a local Walmart.

"I had a number in my mind that I thought I was," she told "Good Morning America." The number she actually saw -- 250 pounds -- sent her onto the floor in tears.

Elizondo, who had been both a high school and college athlete, was "heartbroken" she said.

"I couldn't believe I let it go that far that fast."

Elizondo, from Edinburg, Texas, started her transformation on Jan. 1, 2018. It would result in a 100-pound weight loss by February of the following year.

Starting small

"I knew I didn't want to make drastic changes," she said. At the time, the majority of her diet was made up of fast food. She would go to Little Ceasars, she said, and eat a whole pizza herself.

"If there was a burger meal, I had to upgrade it," Elizondo said of her fast-food habits. She decided to cook at home more and limit her fast-food consumption to twice a week.

She started moving

The next month, she began walking around her neighborhood. The month after that, she started using the elliptical for 30 minutes every day.

In April, her walking turned to jogging. Eventually, she ran a 5K. Then a 10K. Today, she's has her sights set on a half marathon.

She cut back on socializing

"I had to put my health first," Elizondo told "GMA." For her, that meant skipping meals out with family and friends. "They know me and I knew if they saw me order a salad they would ask about it," she said. "I just wanted to avoid that situation."

There was a time where Friday nights were spent jogging and drinking water, she said.

Today, with 100 pounds gone, she's back to socializing regularly and spending time with her family and friends. "They know I've worked so hard and understand where I'm coming from."

She used a meal-tracking app

My Fitness Pal, Elizondo said, not only helped her lose the weight, but now helps her maintain it.

"It's still my best friend," she said. Her favorite features are how the app gives calorie suggestions and allows users to upload photos so she can see her progress with every milestone reached.

"It took a lot of consistency and discipline," she said. "Now I don't track as closely to the dot as I used to, but it helps me choose well during the day if I am going to be going out with friends that night."

She learned to love herself

The hardest part? "Learning to love myself at every weight," Elizondo said.

"So many people say they will be happy when they reach a certain weight," she said. "But you have to learn to love yourself at every stage.

"With every goal you accomplish, self-love helps you get to the next step."

Editor's note: This was originally published on Sept. 18, 2019.