It wasn't until a day with her little daughter at the beach that Christine Carlos realized she needed to improve her health. While trying to keep up with her daughter in the sand, Carlos realized she couldn't play with her daughter how she wanted at her current weight: 225 pounds.

Carlos gained a lot of weight as a late teenager. She'd tried to lose weight before, but it always fluctuated.

"I guess due to depression from moving away from the country I grew up in. I found comfort in food, became lethargic and really shy," she wrote.

So with the motivation to take control of her life and be healthy for her daughter, Carlos started a remarkable weight-loss journey.

"I started slow by changing some habits little by little," Carlos told PopSugar.

Within one year, she dropped 100 pounds

The changes she made were simple. And similarly, her advice is simple, but so good for those hoping to lose weight.

"Take it day by day. Don't think about the long term and just focus on what you need to do at the moment, because if you focus on how you want to look, you'll easily get discouraged," she said.

Some of the little changes she started with were as follows:

Low carb, high veggies ... and sweet potato fries

She stopped eating processed foods and mostly ate vegetables and minimal carbs. She did, however, allow herself one cheat meal a week, because she thinks it's important to love yourself in the journey. Her go-to cheat meal was a burger and sweet potato fries.

A normal day of eating usually consisted of oatmeal and eggs for breakfast, salad with a homemade vinaigrette for lunch and fish and veggies for dinner.

Carry a gallon of water around

To help herself not overeat, Carlos drank a gallon of water everyday. It helped her to carry a gallon around that she had to drink before she went to bed. Eventually she switched to carrying two half-gallons of water around. And if the thought of gulping down that much water makes you cringe, she used some flavoring (zero-calorie kinds) to make things a little more exciting.

Get moving

Full on running can be way too intimidating sometimes. That's why Carlos started by just walking on her treadmill to get her heart rate going for 45 minutes. As she began to lose weight, she started jogging. Now she primarily lifts weights, which she said increased her weight loss and reshaped her body.

Think about fitness as a lifelong journey

If you're hyper focused on the ups and downs of everyday weight loss, you're going to be discouraged. If you want your weight loss to be long term, make a lifestyle change. Don't just go on a diet.

"I have good and bad days just like everyone else," Carlos wrote. "What matters is that even if I feel like I'm failing at some point, I keep going and I try my best everyday. My goal right now is to be stronger and build the best body I could achieve in the healthiest way possible without going to extremes. A fitness journey doesn't have a finish line."

If you're interested in other amazing weight loss journeys, check out these changes REAL women made to lose over 40 pounds.