'Sugar-free' grandmother accused of cosmetic surgery

A 70-year-old Perth grandmother who credits her youthful looks to a sugar-free diet has come under fire after appearing on British TV with viewers accusing her of having surgery.

Mother-of-four Carolyn Hartz appeared on This Morning breakfast show on Monday to talk about how giving up sugar 28 years ago had helped her maintain her trim figure and glowing complexion.

But many viewers took to Twitter to question Hartz’s claims, alleging there was more to Hartz’s youthful appearance than banning the sweet stuff and that she must have had cosmetic surgery.

'"I don't eat sugar blah blah can have toxic s--- injected in my face". Her forehead can't even move.”

“'Are we supposed to believe she looks so young through healthy eating?! You can clearly see she's had work done on her face!'” another wrote.

Hartz previously told Australia’s Today Show she had decided to overhaul her diet almost three decades ago when doctors diagnosed her with pre-diabetes 2 and recommended medication.

“That gave me a fright,” she added.

"I was told to take drugs, and I decided to do some research. Like many others — and I know how they feel — I was in denial. I was a sugar addict."

Before her shocking diagnosis, Hartz said she was not overweight and looked incredibly fit.

But she revealed she could easily consume a cheesecake for breakfast or an entire pack of biscuits in one sitting.

Hartz says after she committed to a sugar-free diet, she began using a natural sweetener Xylitol instead, which she said inspired her recipe book called Sweetlife.