(CNN) -

It was supposed to be her birthday getaway, but it ended up being a miserable trip.

Sarah Evans took two weeks off for her 30th birthday in September 2012 to visit Las Vegas with her best friends. Yet she couldn't enjoy herself because of constant thigh chafing -- "I went through an entire bottle of Gold Bond powder" -- and she hated how she looked in every photo.

"All these girls were enjoying themselves in bikinis poolside, and there I was, trying to cover up and hide," she remembers.

Evans decided then and there that she was going to enjoy her future birthdays.

The 5-foot-4 Shreveport, Louisiana, resident weighed 248 pounds at the time, which she attributes to a lifetime of bad eating habits.

"Growing up in the South, eating large portions at every meal was a must," she said. "Breakfast included bacon, eggs, sausage, pancakes and biscuits. Lunch was some sort of fast food, and dinner included a three-course meal of fritters for appetizers, fried chicken, collard greens, macaroni and cheese, and corn bread."

Then, of course, there was creamy banana pudding or homemade apple pie for dessert.

Evans downloaded the "Couch to 5K" app and set two goals: run a 5K without stopping and lose 30 to 40 pounds.

"When I started the program, I couldn't run more than 30 seconds," she wrote in her iReport. "Now I'm running two or three 5Ks a week. Somewhere along the way I fell in love with running."

She soon added CrossFit classes and other forms of cardio into the mix, meeting her original goal and steadily setting new ones, like getting below 200 pounds and improving her 5K time.

Slowly but surely, she was taking back her life.

"Trying to stick to this routine has taught me the importance of encouraging myself, because I didn't have a support system in the beginning," Evans said.

She also switched to a low-carb diet. Now, she typically eats yogurt, hard boiled eggs and turkey bacon for breakfast; chicken salad or tuna for lunch; steak, fish with kale or baked chicken with green vegetables for dinner; and cheese slices, nuts or Jell-O for a snack.

She will take the occasional weekend off from her diet, though.

"It's what you do consistently that matters," she said.

By May of this year, Evans was down to 128 pounds, a 120-pound transformation.

Despite being at it for almost two years and surpassing her goals, Evans said she still has good days and bad days.

"I still have my demons internally that I'm still working through, and even though I have lost weight, I look in the mirror and see flaws," she said.

Running, she believes, has been key to her weight loss success. Her routine often has her in bed at 9 p.m. and waking up at 3:30 a.m. to start on cardio and weight training at the gym. She then runs or takes fitness classes five nights a week.

"We all have things we secretly want to try, but we either don't have the courage, don't have anybody to do it with, or we can't physically do it," she said. "I always wanted to run a 5K but couldn't walk a mile without dying. Now I love running! I don't have to worry about breathing heavy after 30 seconds."