"I didn't know that I had the potential to be this athletic," Massy Arias tells PEOPLE

By Gabrielle Olya
Updated September 16, 2015 02:35 PM
Credit: Sarah Orbanic

Massy "Mankofit" Arias has a super-toned physique – which is very apparent to the 1.8 million followers who track her workout and diet tips on Instagram – but the Dominican Republic-born personal trainer wasn’t always so fit.

“I’ve always been very skinny,” Arias, 26, tells PEOPLE. “I wasn’t born with a typical Latina body.”

The L.A.-based health coach only got into fitness as a way to cope with severe depression. In Arias’ early 20s, the combination of an abusive relationship, dealing with the trauma of a brother sick with cancer, and a genetic predisposition to the condition sent her in a downward spiral.

“I spent seven months in a dark room,” she says. “I would not shower. I started losing my hair.”

Her mother, a nurse, was determined to have Arias work through her depression without the use of medication.

“My mom did not want me to be a zombie or dependent on pills, because sometimes the side effects are worse than the disease,” she explains. “We tried hypnosis, therapists, herbal treatment – nothing was really helping.”

So Arias turned to exercise as an outlet. She started sharing her fitness journey on Instagram, when a single photo catapulted her to the start of social media fame.

“I posted a picture of my stomach and it just blew up,” she says. “All of a sudden I had 10,000 followers. People started adding me and asking me questions.”

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Because she had no background in fitness, Arias began going to the library to research the best ways to get fit so she could provide her followers with answers.

“I started getting information, trying new things on my body,” she says. “I didn’t have a personal trainer because I couldn’t afford a personal trainer, so I started doing things myself and researching.”

Not only did her focus on fitness improve her physical health, but her mental health as well.

“I started making really good progress and got into a better state of mind,” says Arias. “I was weight training and feeling much better, and decided to pursue personal training. I started getting all my certifications.”

Arias has made a complete 180-degree turn from where she began.

“I had no background in sports and I wasn’t athletic,” she says. “Today it’s a different story. I didn’t know that I was going to be able to do all the things that I’m doing now. I didn’t know that I had the potential to be this athletic. I think it’s just that the energy you put out, you get back.”

Now Arias hopes to take everything she’s learned and share it with her fans and followers, so that they too can improve their lives.

“My goal used to be to change the world,” says Arias – who recently launched an online 30-day fat loss challenge. “I’m not going to change the world myself, but hopefully those that I am inspiring and motivating and educating will educate those around them. That’s how we’ll make a difference.”