In an earlier Bored Panda interview, Denise, who has become an empowering influencer, said the project started back in early 2019 when she and Maria would pose for photos wearing the same bikini.

It did so well and people loved it so much, the two of them simply continued doing it here and there. Meanwhile, their follower count started growing, and when the pair shared their very first video on TikTok, it quickly got over 1.5 million views. "Once TikTok had become popular, we decided to do a fun video and that’s when it went viral," the style influencer said.

They then realized it was time to come up with a hashtag of some sort and start an actual body-positive movement since so many women found their videos so inspiring. They let their Instagram followers vote between #ThroughThickAndThin and #StyleNotSize, and the second option won.

Denise said that their key message is "to dress however you please and to love your body." She also added that it’s time “to stop comparing yourself to others.” Feeling confident in your own skin is what makes everyone shine from within.

She explained that “the fact that we can inspire so many women to feel confident and be themselves makes us want to continue this movement.” The pair is over the moon to receive so many positive vibes from people on social media.

"I see girls commenting (on social media), 'I wish I looked like you,'" Mercedes told TODAY about the mindset they're trying to reverse. "Everyone is on social media 24/7 right now, and it can brainwash you into feeling bad about your body."

Castellanos added: "For us, it was trying to get rid of negativity ... Everything on social media is, 'This is how you’re supposed to look.' ... We’re giving you a hand and telling you to be yourself."

Mercedes said she has girls telling her she's helping them to feel more confident. "I wish when I was younger that I had someone to look up to. Back when I was 16 in 2008, it was always just a struggle to be skinny. I’m glad things are changing now."

Castellanos hopes the success of their movement can one day change how existing fashion companies determine their size selections.

"It's been tricky to find brands that sell sizes zero to 20," she said. "We hope they can see there are a lot of different shapes and sizes and provide them clothing, as well."

The two friends are dreaming about starting a clothing collection that isn't organized around size, unlike stores like H&M and Forever 21, which have separate sections for plus-size items, Mercedes said.

Of course, they want to continue to spread body positivity as well, especially for the younger generation.

"I would love to see women just be themselves," Castellanos said. "I want them to be like ‘Oh my God, I wore this crop top, and I look good.' I want to feel like nobody cares anymore."

In July, Ascena Retail, which owns leading US plus-size clothing retailer Lane Bryant (sizes 12-28), filed for bankruptcy, with over 150 Lane Bryant stores scheduled to close. Lane Bryant, along with Ascena's other brands, is now being sold to Premium Apparel, an affiliate of Sycamore Partners. Taking a broader look across the fashion market, in an era of retrenchment and cost-cutting, some think the higher manufacturing costs of plus-size apparel are likely to set back investment for the future. But researchers say that represents a missed opportunity.

Plus-size in the US alone is growing at nearly twice the rate of the overall apparel market. According to the report published by Allied Market Research, the global plus-size clothing market garnered $480.99 billion in 2019 and is anticipated to reach $696.71 billion by 2027.

Around 70 percent of women in the US wear a size 14 (EU 44, UK 18) or larger. In the UK, the average woman’s clothes size is 18, while EU countries follow a similar pattern. But less than 20 percent of apparel is made in those sizes. Plus-sized consumers have faced limited design options as well as inferior quality.

There is, however, a silver lining: leading retailers and brands, such as Walmart, Marks & Spencer, and giants like Nike, Puma, and Adidas, have all developed plus-sized lines. And in the US, Universal Standard, founded in 2015, has taken size inclusivity to a new level, selling clothes up to size 40.