“When I started with the world tour, I thought: wow, this is really getting serious,” says Kayla Itsines.

World Tour? This is not about a new Beyoncé or Adele. Fans from all over the world are crazy about doing workouts with Australian fitgirl Kayla Itsines, always dressed in a sports bra, colored pants and her characteristic ponytail hairstyle.

Itsines talks to Business Insider about the amazing success on social media and the international business she build from that: “Of course, we were amazed by the number of girls and women that wanted to participate in the international tour.” Her first tour to the US in 2015 was sold out within in less than one hour.

Elsewhere the response was the same, says Itsines: “I still remember someone saying: ‘Don’t expect to much if you go to Amsterdam, Dutch girls are not really into this kind of thing.’ There was space for 2.000 people and it was completely full. Just happy girls and women jumping around, while temperature was 30 degrees Celsius.”

As a teenager Itsines started working as a personal trainer in her home town Adelaide. A cousin pointed out she could do something with Instagram: posting pictures of the transformation of satisfied customers. At that point Itsines had no idea how impactful these photos would become.

Bikini Body Guide

Soon her Instagram profile got a lot of attention and Australians were craving for details about her workout program. Itsines developed an online sports and eating program called Bikini Body Guide. The workout focuses on arms, legs, abs and bottom. The main goal is to make women feel bikini-confident.

Within less than five years she created a truly global fitness hype, allowing her to set up a business around it with her partner Tobi Pearce. The BBG brand now has e-books, hard copy books, apps and other products. This year Forbes put her in first place worldwide as the top influencer in the category fitness.

When asked if she feels like consciously building a business, she has to think for a moment: "Yes, well, I've been working for myself since a was 18. Maybe I did not see myself as an entrepreneur, but I knew what I wanted to do: help women. That happened to happen under the heading 'entrepreneur'. I love entrepreneurship! Being in this position is great, so I can accomplish my mission. The world needed such a thing."

Itsines turned out to be a great inspiration: thousands of women worldwide spent $ 19.99 per month on Bikini Body Training. They share their progress through the hashtag #BBG, an abbreviation for the Bikini Body Guide.

#BBG - together with other related hastags - already has more than 10 million interactions. Itsines herself has about 7 million followers on Instagram, where she shares photos of transformations of her followers, and also posts selfies and pictures of her dogs.

Organic growth

"It's actually been growing very organically. I never expected this to become so big, but I'm very grateful," says Itsines. "Our team has about twenty people. Unbelievable, when you think that when we started it was just me ... and Tobi who answered the email."

The key to her success comes from social media. "Without Instagram, it would never have become so big," Itines explains. "I'm also terribly grateful for the existence of platforms like Facebook and Instagram. Many people say social media can be a blessing and a curse. We have always been able to use it for the good."

She never worked with a deliberate social strategy, Itsines says. "The only plan I had for social media was to reach more women. I never wanted it to be about me and my life."

People respond to things they feel are genuine, she discovered. "When people see you care, they want to follow you. Then they want to know about everything you do."

Itsines has been on the cover of magazines like Cosmopolitan, Women's Health and Glamour. But she hasn't adopted a rockstar attitude. On the contrary: "Haha, I'm the one who's always super nervous to meet all the girls. I follow their journey to health on Instagram and Facebook intensively. To me they are like family - even though I know they're not."

Training @tamminsursok this morning😁 "Tam, stop talking"... "but kayla, I'm funny" 😂 www.kaylaitsines.com/app

Een bericht gedeeld door KAYLA ITSINES (@kayla_itsines) op

Responsibility

7 million followers on Instagram, mostly young girls who want to lose weight. It sounds a little tricky: how about the risk of girls getting too serious about this? Itsines: "I always try to make sure my message is clear. It's about how they feel, not how they look." Adding to this: "It's not about me, it"s about the girls. What I try to show in my book that it's ok to enjoy both eating and doing sports. "

Does Itsines sometimes regret calling her product 'Bikini Body Guide', as some media suggested? "It's not that I'm sorry, it's more that in the beginning I didn't know it would go so far beyond Adelaide. The frase has different interpretations in different countries. Fortunately, I can now show that a bikini body is not a body type, it's about bikini body self-esteem."

In 2016 her app 'Sweat With Kayla' was the fitness app with most downloads on both iOS and Google Play, according to business intelligence firm App Annie. Sales proceeds were estimated at $17 million by App Annie.

In May this year Itsines launched an new app called SWEAT. "It allows you to select different trainers and see what program you like." SWEAT includes Kayla's new workouts - including a new BBG Strong - and programs of two other fitness influencers, personal trainer Kelsey Wells and yoga teacher Sjana Elise Earp.

"I don't care much about money and fame," Itsines says. "That's why I said yes to SWEAT." She could have focused on her own business, but instead chose to work with others to reach more women.

She is glad being part of the app "next to Kelsey and Elise," Itsines explains. "I just hope to help women as much as possible, from post-pregnancy to people with fears and depressions who could be helped by yoga. I try to do everything to achieve that."