From BBG To The Sweat App: Kayla Itsines Shares Her Career & Fitness Journey

“Sometimes I think about what I would say to my 18-year-old self if I could go back in time.”

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Sweat

July 8, 2025 - Updated July 8, 2025

Kayla Itsines in gym white activewear

Ever wondered how an 18-year-old personal trainer from Adelaide went from training women one-on-one in her parent’s backyard to becoming one of the most recognisable faces in fitness? 

After releasing a PDF guide featuring the exact program she was training her clients with at the time, our co-founder and head trainer Kayla Itsines quickly became a household name with thousands of women from every corner of the globe following her iconic workouts.

Ultimately, that journey led to her co-founding Sweat, a leading women’s fitness app and global community that’s transformed the lives of millions of women from Sydney to Singapore to San Diego. Pretty cool, huh? 

Where it all began

“Sometimes I think about what I would say to 18-year-old me if I could go back in time, standing in my parents' backyard with a whiteboard, training my clients with absolutely no idea where this journey would take me,” shares Kayla about the early days of her career. “Back then, I was just a personal trainer who was passionate about helping women feel strong and confident in their own skin. I never imagined that passion would turn into a global community… or that I’d become the co-founder of an incredible business like Sweat.” 

“I was so young, I was living with my parents, I was training women in their backyards, at the beach, at a women’s only personal training centre, I was going to people’s houses. I was doing everything I could for women, from Adelaide in South Australia…. And then I downloaded Instagram.” 

When Kayla first joined Instagram, there were no Reels, no Stories, and no fitness influencers. 

“I was just a personal trainer, online, sharing my life and my clients’ transformation photos and… it just took off.” 

Kayla was in her early 20s when her online presence began to skyrocket, reaching thousands of women around the world at a time when she had never left Australia. While she was still training her clients in Adelaide, she was suddenly inundated with requests from women who wanted to work out with her - even if that couldn’t be in real life. 

“People were asking me for my workouts so we wrote them down and we made a PDF and it was exactly how I was training my clients at the time. It was a 12-week program with three workouts a week and they were 28 minutes,” Kayla shares. 

“I was hesitant to release the guides because I’m a trainer and I wanted to be there training women in person. But then I thought, these guides are empowering women to work out by themselves and giving them that confidence.” 

And so, Kayla’s BBG guide (known today in the Sweat app as OG Kayla) was released.

The guide quickly went viral 

Soon after making the guide publicly available, it went viral, with women around the world downloading it and sharing it with their friends. To this day, there are millions of Instagram posts using the #BBG hashtag. 

It didn’t take long for a simple 28-minute workout to become a global fitness movement. 

“I went from training women in my parents’ backyard to training them by the thousands at bootcamps around the world,” Kayla says. “It was wild to see because when I started, women weren’t represented. There were female-only sections with just three treadmills and a handful of mats in the gym. There weren’t female-first training programs and barely any activewear choices. And now, the biggest names in the fitness world are women.” 

“Clearly I did not think this was going to go viral,” Kayla reflects, going on to explain how they landed on the name. “I worked for a bootcamp that was originally at the beach called the Bikini Body Bootcamp and people knew me from that bootcamp. When I was releasing the guides we just called it the Bikini Body Guide from the Bikini Body Bootcamp, then the community changed it to BBG.”

“If my grand plan was for it to be a brand, I would have put more thought into the name. But it wasn’t ever meant to be a brand, it was meant to be a guide. I was forever explaining that it had nothing to do with a bikini but everything to do with how confident you felt.”

When the PDF was first released, “bikini body” was a common fitness term but as the industry shifted, Kayla ultimately made the decision to remove the “BBG” terminology from the Sweat app. 

“The name began to represent an outdated view of health and fitness, so I changed it,” says Kayla. “This was a huge moment for me personally as the BBG name was so well known and was a huge part of not only my journey, but the Sweat Community’s journey.” 

“Sweat’s mission is to help empower women through fitness and that is right down to the language we use, too. Since becoming a mum, I’ve become even more aware of how important it is that we use language that empowers women. I want to use language that is positive and inspiring for all women and that is the world I want Arna to grow up in.”

“I’m proud that as a company at Sweat we can look at something and think ‘that’s not good enough’ or ‘that’s not right anymore’ and make the relevant changes.”

“I’ve been online for over 10 years now offering free education for women and all the while trying to stay so true to my values as a trainer,” Kayla shares. “Although there are definitely things that I would have done differently, I think my journey was reflective of what the industry was like at the time. 

“I was working with what information I had and it’s been the biggest learning and the biggest journey. I am definitely not perfect but I am always trying to do better and be better, whether that’s for me, for Sweat, for the community or how I use my platform.”

Kayla Itsines sweat app food section

Founding the Sweat app 

Kayla’s approach has always been female-first, but she quickly realised that if she wanted to continue to empower and show up for a global community, it had to be bigger than her. And that’s why Sweat exists. 

After first launching the Sweat with Kayla app as a digital home for the BBG program, the app became Sweat in 2017. Today the app is home to over 60 unique programs created by some incredible female personal trainers, more than 13,000 workouts and hundreds of recipes

“The Sweat app was created in a time where there was barely anything for women, barely any fitness apps and all I wanted was a fitness app for women to be able to train - however they want. We wanted to have a nutrition element with recipes, make different training styles available and make sure there is something for everyone.”

“I’m SO proud of how far Sweat has come, but it hasn’t always been easy,” Kayla shares. “There have been long days, self doubt, mistakes and plenty of lessons along the way.”

“But through it all, one thing has never changed, and that is my love for helping women move their bodies, build their confidence and feel empowered every single day.”

Kayla Itsines Strength program

Her ever-evolving fitness journey

“The original PDF guide definitely reflected how I trained at the time. High intensity interval training has always been a key part of my routine and I love HIIT training,” Kayla says of her own fitness journey. “Like any woman, you want to change up your training over time and I’ve been really candid about that.”

“I’m a different woman at 34 to who I was at 20. “I’ve had two kids, two postpartum journeys, endo surgeries, sickness, personal loss and my own setbacks. Now that I’m in my 30s, strength training has become such a big part of my training mix.”  

Earlier this month, Kayla released the program the Sweat Community has been eagerly anticipating: Strength with Kayla.

“These are the exact strength workouts I've been following over the last few years, and I’ve never felt better,” Kayla shares. “This is the routine that has me feeling like my strongest, most confident self, and now it can be your routine, too.”

“No matter what I’m going through, fitness has always been a part of my life and I’m so proud that Sweat offers something for every stage.”

Kayla knows first-hand what it’s like to juggle fitness, family and work, which is why she’s so passionate about helping the women in her community move with confidence throughout every stage of life with her 12 programs.

Female first, always 

“I am so grateful for my community,” shares Kayla. “They are the most amazing and supportive women I have ever met. From me being able to support them to them literally supporting me in every stage of my life, from watching me be a little kid to growing up to be the woman I am today - they have been there every step of the way.” 

There is so much to love about the Sweat Community, an amazing group of women that span every corner of the globe. They strive not only to be the best version of themselves, but to empower the women around them. 

One member who has left an indelible mark on Kayla, the community and the entire Sweat team? The incredible Deb (who shared her story as @fitwithsweat), who showed us time and time again what it means to be a  strong woman before and after her passing in 2022. 

“It’s not just my community that inspires me but the women in my life. The amazing women that work at Sweat, my family, my friends, the people that I meet day in and day out. These women are so powerful and so incredible and so supportive and I’m so grateful.”

Join the incredible Sweat Community

We know we're stronger together

Train with Kayla in the Sweat app 

“As a trainer, all I want is for you to feel strong in your mind and your body, whatever that looks like for you,” says Kayla.

Today, Sweat is home to over 60 programs designed by some of the world’s leading names in fitness for women of every fitness level. Kayla has 12 programs for you to choose from, from OG Kayla (originally the BBG PDF guide that launched her career!) to her brand-new Strength with Kayla program.  

“To every woman who’s ever trained with me, used the Sweat app or simply showed up for herself, thank YOU. You’ve helped me grow from a young personal trainer in Adelaide to someone who is part of the most incredible global community of women, and I can’t wait to keep growing with you.”

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* Disclaimer: This blog post is not intended to replace the advice of a medical professional. The above information should not be used to diagnose, treat, or prevent any disease or medical condition. Please consult your doctor before making any changes to your diet, sleep methods, daily activity, or fitness routine. Sweat assumes no responsibility for any personal injury or damage sustained by any recommendations, opinions, or advice given in this article.

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