By Gabrielle Olya
Updated October 14, 2016 02:27 PM
Credit: Source: Sia Cooper/Instagram

Sia Cooper has amassed over 287,000 followers on Instagram thanks to her fit mom tips – but she wasn’t always so in shape.

“When I was overweight, I actually did not exercise because it was not a priority,” Cooper, now 27, tells PEOPLE. “My diet was crappy because I was a college student living off of $1 Burger King burgers and Chik-fil-A kids’ meals. I would also skip meals, which slowed my metabolism down. I did not know anything about health or fitness because I was never taught it. I simply had no idea where to begin and the thought of cleaning up my lifestyle made me anxious.”

The Destin, Florida-based fitness specialist reached a breaking point when she began waking up every day without any energy.

“As a 20-year-old, there was not one reason why I should have felt like such an old lady!” she says. “All of the alcohol, cigarettes and junk food were slowly poisoning me and I did not want to spend the rest of my life living that way. After constantly telling myself over the years that I would start this or that new diet on Monday, I had a friend tell me to watch [the documentary] Food, Inc. This was a major turning point in my life.”

The documentary inspired her to remove all of the junk food from her kitchen.

“I remember heading straight towards my pantry and throwing out the chips, cookies, soda and anything else processed that I could find, and I made a new grocery shopping list with healthy foods,” says Cooper. “I had no idea what quinoa was and I hated veggies with a passion, but I taught myself to love all of that by learning to cook for myself for the first time ever. By cooking my meals at home, I was able to know exactly what went into my meals and how many calories I was eating.”

Cooper is now a mother of two children, but she didn’t let her pregnancies derail her new healthy habits.

“I stayed on track during pregnancy by remembering that everything that I do affects my unborn baby,” she says. “What I eat, they pretty much eat as well. I remember craving chips and queso with my son and lots of chocolate with my daughter, and I did indulge a little, but I worked out as well.”

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And after giving birth, Cooper made sure to make an effort to continue to eat healthy and make time for workouts.

“It can certainly be a task when you are trying to take care of a newborn baby and yourself,” she says. “It takes a little time to readjust, but I firmly trusted that with a clean diet and proper workouts, I would get stronger.”

Cooper – who gave birth to her daughter just four months ago – says she loves her body now more than ever.

“The truth is you will never ‘get your body back’ because your body will never be the same. That does not mean it cannot be better because it totally can!” she says. “You hold the key to what your body can do.”

Cooper says she appreciates her body now more than she did before becoming a mom.

“I feel better about my body after having kids because I am amazed at what my body has accomplished, from growing two tiny human beings to birthing them,” she says. “Yes, motherhood has definitely changed my body, but I feel stronger than ever. I love my new curves and my new shape. Though it’s different, it tells a damn good story!”

She hopes to serve as a positive role model for her two young children.

“My kids are the reason why I wanted to gain muscle and strength,” says Cooper. “All of my life I wanted to be skinny – but ‘skinny’ is not what I want to teach my children. I want my kids to grow up to be confident in themselves regardless of their looks. They are the reason why I want to be strong and healthy.”