Last year, I spent four months working my way from sedentary to active. I'd gone from breaking a sweat just walking up a flight of stairs to running miles every day on the treadmill. Believe it or not, my motive couldn't have been any less superficial at the time — I wasn't trying to lose weight or look like a Sports Illustrated model. No, my husband and I were planning to start a family soon, and I was simply getting my body ready for a healthy pregnancy.

Eventually, I was ready for something different: Proud of myself for getting in shape and a little bored with my workout routine, I wanted to keep the momentum going and find a new challenge. That's when I started noticing some of the "fit girls" I followed on social media tagging their pictures with #deathbykayla, #kaylasarmy, and #thekaylamovement. I didn't know who Kayla was, but rumour had it her workouts were hardcore, so I wanted in! With a little digging, I discovered that Kayla is an Aussie trainer named Kayla Itsines, and her gruelling program is called the Bikini Body Guide. Even back then I cringed at the name, but charmed by the promise of a challenge, I thoughtlessly clicked the follow button and handed over $48 (£32) for her program.

Over the course of the next 12 weeks, I got what I wanted — burpees, push-ups, sweat, endurance — yet at the end of the programme, I had more body issues than when I'd started. How’d that happen?

Following Itsines on social media was an education on what a “bikini body” is. Her Instagram feed is a gallery of six-packs, thigh gaps, and bubble butts — a steady stream of superficial inspiration that’s scored her five million followers, more than Jillian Michaels, Shape magazine, Shaun T, and Dr. Oz combined.

I quickly learned that her brand seemed less focused on the physical challenge the hashtag #deathbykayla had suggested, and more on aesthetic results. Her marketing strategy relies on snapshots of her own sculpted abs along with transformation photos of the young women who’ve used her programme. Before and after pictures that make you think: If strangers on the internet can achieve this ideal, so can I! Sprinkle in some pseudo-empowering messages, and voilà. All of this fitspo isn't supposed to be about getting skinny; it’s about “inspiring” an audience. After all, look how much happier she is! Strong is the new sexy! You can’t fake fitness!

I fell for it.

Within a few weeks, a major shift happened to my motivation and mentality. I was no longer focused on the intrinsic benefits of exercise — endurance, endorphins, energy; instead, I was hung up on how toned my abs, arms, and legs looked — the “proof” of how fit I really was. Like Kayla says, you can’t fake fitness. Exposing myself to her version of a bikini body brainwashed me into believing I needed to look like the girls on her page to validate my healthy lifestyle. I was Pavlov’s dog in a case of classic conditioning — trained to associate the bikini body with health.