A dietician has issued a warning against the use of popular weight loss programs endorsed by fitness celebrities online.

Many are turning to online fitness stars like Ashy Bines, Tone It Up BFFs Katrina and Karena and 25-year-old wunderkind blogger Kayla Itsines to achieve their new year health goals.

But Sydney dietician and nutritionist Laura Iredale is not convinced by the promises of these celebrity fitness programs.

“My issue with a lot of them is the fact that they are a sort of quick fix, and they’re not a long-term solution,” Ms Iredale, a Sydney dietitian and nutritionist, told The New Daily.

“So people can find that they will get results in the short term but it can even set them back further long term. It’s not something they can sustain for a very long period of time.”

Fitness model Ashy Bines hit headlines this week after News Corp published the accounts of customers accusing her business of taking unauthorised payments from their accounts.

It’s the latest in a series of controversies involving the 29-year-old. In 2016 Bines was in hot water after an Instagram post criticising plus-size model Tess Holliday, whom Bines said was not “a role model” and “not healthy”.

Ashy Bines shared an instagram post criticizing plus-size model Tess Holliday. Photo: Instagram/AshyBines

She’s also courted controversy for frequently using the disabled parking space directly in front of her gym, though she does not hold a disability permit.

The fitness model’s empire includes everything from a fitness app (Ashy Bines Squad) and a gym (the Transformation Centre), to her own line of active wear and “clean treats”. She also sells access to her Bikini Body and Booty challenges, both 12-week fitness programs.

Ms Iredale said many of these short-term health programs combine severe eating and exercise plans over short bursts, often for people who have never tried high-intensity health training before.

“Often it’s too extreme in terms of eliminating too many foods or food groups, so it can become quite boring and can also even lead to potential nutrition deficiencies,” she said.

“People are going from zero to these extreme fitness regimes so there’s lots of issues with that in terms of injury and overuse and that type of thing.

“And some of them can be quite expensive as well, which isn’t possible for everyone.”

Fitness model Ashy Bines promotes her online health programs on Instagram. Photo: Instagram/AshyBines

“The main issue is it’s just too extreme in what their limiting or what their expecting of people, sometimes even to the point where people aren’t actually getting enough energy or nutrients to stay on it long term. And they have no guidance at that point.”

Australians spend an average of $2340 per household on everything from protein shakes and nutrition plans to wearable exercise technology and fitness programs, according to a 2015 report.

In an Australian Bureau of Statistics study completed last year, gym memberships and fitness programs were the second highest-ranking exercise technique used by Australians for fitness participation, behind “walking for exercise”.

Ms Iredale said there was no one-size-fits-all protocol for weight control or healthy living – nor is there a quick-fix solution.

“In some ways [these programs] can be a good kick start for people, but they really just need the guidance after that,” Ms Iredale said.

“I’m a big believer in more gradual and smaller changes that people can stick to.

“It doesn’t get immediate results, which does make it more challenging in the short term, and frustrating. But I think it’s all about balance, and even just finding a few small tweaks a week that you can stick to and build on does work a lot better in the long term.”

The New Daily reached out to the Ashy Bines Company for comment but received no response.