"We'll talk about everything and we'll talk about things that women don't want to talk about on social media like when we have our periods or when we feel bloated or when we miss a workout," she said.
"We all get bloated, we all have stretch marks, it's just completely 100 per cent normal. We talk about those things to make it more real."
And Ms Itsines, who recently spoke out about being branded "too skinny" on Instagram, predicted an imminent groundswell against negative body image messages online as more women rebelled against them.
"Coming in 2018 there's going to be a big trend focusing on body confidence," she said.
"There are some girls on social media at the moment who are pushing this big (idea) that it doesn't matter what you look like, it matters what you feel like, and that's what we're pushing as well."
Ms Itsines said some of her favourite examples of inspiring women railing against online stereotypes included the joint account of Australian models Kate Wasley and Georgia Gibbs that showcased women of different shapes standing together, and mother Lexie Woodmansee who shared the unfiltered, sometimes unglamorous stories behind her fitness journey.
Ms Itsines said exposing what goes on behind the scenes of a photo can help shut down unrealistic expectations and create more supportive online environments.
"It's really important to talk about why you took that photo ... or the hard work that goes into everyday life, or goes into yoga, or becoming a mum, or after you have a baby," she said.
"You have to talk about those things. What's the point of social media if you're just going to upload a photo and say nothing? Our aim is to motivate and inspire."
The fitness entrepreneur is well placed to make an impact, having recently published a book, finished a worldwide stadium tour with stops including London and New York, and established a growing global audience for her Sweat app, which features workouts in eight languages and last year became the richest fitness app in Apple's Store.
Ms Itsines said adding yoga and post-pregnancy workouts to the app from Ms Earp and Ms Wells - friends with their own online communities - was designed to expand its reach and give variety to her loyal followers, some of whom are now on "week 159" of her workouts.
While Ms Itsines has been building her fitness brand since 2014, and now boasts more Instagram followers than high-profile health commentators Gwyneth Paltrow and Jillian Michaels, she said more Australian fitness experts were "definitely" seizing opportunities to grow a similarly strong international following.
"And good on them," she said.
"There's a lot of communities young entrepreneurs have built up through fitness and that's the aim. That's how you keep your brand for a long time."
Former Biggest Loser trainer Michelle Bridges exported her multimillion-dollar 12-Week Body Transformation program to the United States, for example, and former reality TV bachelors Sam Wood and Tim Robards have launched fitness training programs online and in apps to attract a wider audience.
Australia also boasts a growing number of social media fitness gurus with sizeable followings, including Reebok ambassador Emily Skye, and former Olympic pole vaulter turned yoga instructor Amanda Bisk.
FIVE RISING AUSTRALIAN INSTAGRAM FITNESS STARS
โข Sweat app and Bikini Body Guide creator Kayla Itsines
@kayla_itsines: 7.2 million followers
โข FIT health program founder Emily Skye
@emilyskyefit: 2.1 million followers
โข Personal trainer and fitnesswear designer Ashy Bines
@ashybines: 930K followers
โข Australian pole vaulter and FreshbodyFitMind founder Amanda Bisk
@amandabisk: 678K followers
โข Base Body Babes training partners and sisters Felicia Oreb and Diana Johnson
@basebodybabes: 640K followers
