Kayla Itsines responds to Essena O'Neill's 'social media is not real life' post.

Today, an Australian social media star has made international headlines for her decision to ‘come clean’ about her flawless Instagram life.

Essena O’Neill, 18, had accrued almost 600,000 Instagram followers and 250,000 Youtube subscribers who were drawn to the breezy, beautiful, carefree-yet-glamorous lifestyle she depicted. However, this morning she quit social media altogether.

O'Neill's Instagram username has been changed to 'Social Media Is Not Real Life', and she's updated all her existing captions to reflect exactly what was happening in each of her styled-to-perfection photos — with fairly brutal honesty.

"I had acne here ... I was smiling because I thought I looked good. Happiness based on aesthetics will suffocate your potential here on earth," she captions the above image. (Post continues after video.)

Now, inspired by the 18-year-old's "fantastic" candour, another high-profile Instagrammer has shared her philosophy on keeping social media realistic.

Adelaide-based personal trainer Kayla Itstines has almost four million followers thanks to her wildly popular fitness guides, but she's determined to keep her feed as honest and authentic as she can in a world where perfection and artifice tends to get all the likes.

"Three weeks ago, I made a post explaining 'a side of social media that you don't see'. What it REALLY takes. I explained that it's not as simple as posting a few photos of beautiful food, new clothes, luxury items (whatever celebrities post) and ?BAM?, life is amazing," Itstines writes.

"On my account, I'll tell you now, you don't see a lot of things. Not because I don't want to show you, because I cannot physically take a photo of them. Things like... the 5am wake ups, the late nights, the constant bullying, the lack of support and understanding of friends, the stress.... and so much more."

Itstines goes on to explain there are three things she swore she'd never do on Instagram, a promise she's kept since she first launched her profile.

"I would NEVER promote something I didn't believe in (detox, fads, quick fixes), and I still refuse. I would NEVER sexualise myself or pose provocatively to sell anything. I would never only post information that suits my lifestyle," the 23-year-old explains.

Ultimately, Istines says, women should embrace their 'true selves' regardless of what they see on Instagram — or whether it mirrors their own lives.

"My life, my food, my family, isn't YOUR life, everyone is different. I post these [fitness] transformations to show you there are SOOOO many girls out there on so many different journeys ... Don't strive to live like, or be like, one person on social media. Create your own self. Be honest. Stick to your morals and always try and be the BEST person you can be." (Post continues after gallery.)

As Itstines mentions, she shared a post a few weeks ago that touched on this issue — particularly her bemusement at commenters who write things like, "I wish I was her" or "I wish this was my life".

"Instagram is one per cent of someone's life. You only get to see the BEST parts of everyone's day ...new clothes, new hair, amazing holidays, love, happiness ....because we know, no one wants to show off their sadness," she wrote.

"What you don't see is the 5am wake ups, the late nights working, the bullying, the changes in friendships, what it really takes to run a successful life, the long hours, the tears, the lack of sleep, the stress, the pressure, people trying to use you, gaining some things but losing others ... no one sees the other 99 per cent of anyone's life. You see the best parts."

Something to keep in mind next time you're mindlessly scrolling through Instagram and start to feel a bit insecure about the way you're going about life.

Do you think social media is all artifice? Who are your favourite people to follow?