An Australian gym has come under fire for 'fat shaming' after sharing a dramatic transformation photo of a client on social media alongside a controversial caption.

'Let me guess ladies... You feel unfit, unattractive, self-conscious and worthless?' Part of the caption read.

The call to action was an attempt to build their list of clientele but it backfired when a number of women called them out for 'fat shaming' and 'offensive' phrasing.

On Sunday, Adelaide-based HTFU Fitness - which stands for 'Harden The Fat Up' - posted an image of client Danna after she went from a size 16 to eight when training at their gym.

HTFU Fitness - which stands for 'Harden The Fat Up' - in Adelaide posted an image of Danna on Sunday who went from a size 16 to eight when training at their gym (pictured)

In an effort to encourage more sign ups, the team at HTFU captioned the image with what they saw as a motivational spiel.

'You feel unfit, unattractive, self-conscious and worthless... especially when standing in front of the mirror naked,' it began.

'You feel embarrassed and ashamed getting naked in front of your partner...you are sick and tired of picking outfits that hide fat... and you want to feel comfortable in your own skin.

'But there's a problem... you are too afraid to join a gym because you're too embarrassed, ashamed, self conscious and worried about being judged and most of all, you're just too nervous to commit.'

In an effort to encourage more sign ups, the team at HTFU captioned the image with what they saw as a motivational spiel (some members pictured)

The comments and direct tone didn't sit well with many of the members, who ended up lashing out in the comments.

'I'm glad you let your gym culture show through this post. Now I know where not to go! This gym is definitely NOT for anyone who wants to get fit while not being judged, fat shamed, boxed into the 'unfit=unhappy' category and probably ridiculed for not being fit,' one person said.

'Hey! I was trying to find the most negative, off-putting marketing in Australia. Congratulations Guys!!!' Another added.

'So deplorable. Talk about reinforcing the WORST way of looking at a woman's body. Gross,' one particularly fired up woman admitted.

'This is a horrible, horrible way of marketing to women. Worthless? FFS!' She said.

Owner Aaron Cartwright noticed some of the uproar his words had created and decided to address the issue himself

There was a mixture of responses to the now viral post online (pictured)

But not everyone agreed that it was harmful advertising.

'I don't normally comment on these things but I feel like women/anyone just quickly jump on the bandwagon to tell someone they're fat shaming or being sexist these days,' one person responded.

'This post is just writing the truth about what many women feel. If you are comfort able being a bigger woman then that's great for you but there's a hell of a lot of girls out there (myself included) that feel disgusting and worthless because of my weight/fitness levels.'

Owner Aaron Cartwright noticed some of the uproar his words had created and decided to address the issue himself, telling FEMAIL he understood how the words might have offended some.

'Hey everyone, thanks for your comments as we appreciate all feedback good, bad and ugly. However the only thing we would change is the first paragraph as we should have said "Some of you feel..." as not all women feel this way,' he said.

They used terms like 'worthless' and 'embarrassed' because those were the same ones used by clients before they signed up at the gym, Mr Cartwright said

'Apart from that we make no apologies, as if you read it properly with an open mind you would see we're stating the truth on how SOME women feel about themselves at the moment, how they want to feel and what they know they need to do to feel better.

'We had four new females start today as a result of this post, two of them stated they felt exactly how we said above and after their first session today they're already feeling 100 times better and thanked us for helping them have the courage to start looking after themselves.'

They used terms like 'worthless' and 'embarrassed' because those were the same ones used by clients before they signed up at the gym, Mr Cartwright said.

'We're simply stating that we understand the truth on how some of them are feeling at the moment.. but we can understand how that could be misunderstood as 'fat shaming', 'gross' and 'disgusting' to someone reading it without an open mind.'