Fad diets: How to spot a dubious eating regime.

If you are looking to shed kilograms or start eating better, there is no end to the number of fad diets on the market — promising everything from weight loss and detoxification to cures for cancer.

And while some are grounded in solid principles of nutrition, many offer advice that is not backed by any evidence and require drastic lifestyle changes that are unachievable for the average person.

Tim Crowe, Associate Professor of nutrition at Deakin University, said nutrition was a field where people were often considered experts “simply because they’ve got a story to tell”.

So how can you spot the diets to avoid?

Here are Associate Professor Crowe’s top three tell-tale signs of a dodgy diet.

1. Contradicts accepted nutrition and health guidelines

According to Associate Professor Crowe, the first thing to examine is whether the diet you are considering is following the same themes and general messages that are recommended by peak health bodies and credible experts.

“It’s the consistency of the message that’s important,” he said.

“If organisations like the National Health and Medical Research Council (NHMRC), the Cancer Council, the Heart Foundation, Diabetes Australia, and so on are all saying the same thing and you’re hearing something very different, you’re right to question it.

“There is no government conspiracy to make us sick. They want to make us better.”

2. Cuts out whole food groups/focuses on foods with ‘disease-curing’ properties

Associate Professor Crowe said dodgy diets often have a fixation with a particular type of food or a way of eating.

“Buttered coffee comes to mind … loading up on butter, coconut oil, particular foods that are meant to have some additional health benefits,” he said.

In other cases, you are told to exclude whole food groups like grains or dairy.

“If you have to exclude foods for a medical reason, that’s very different to excluding them because you’ve jumped on the latest fad because a celebrity nutritionist has told you so,” Associate Professor Crowe said.

“If you speak to a dietician about foods you need to cut out [because of a health condition] they’ll give you advice about what other foods you need to make up for the difference [in nutrients you are missing out on].”

He said generally no such advice was included in fad diets.

3. Marketed with testimonials instead of scientific evidence

Compelling personal stories about individuals who changed their diet and lost masses of weight or recovered from a horrible illness leave a strong impression on people, Associate Professor Crowe said.

But he said in many cases, the person in the anecdote probably lost weight because they drastically reduced their kilojoule intake, or would have got better anyway, thanks to either the normal remission of their cancer or the treatment they were having.

“You tend to only hear about people who claimed to have beaten a cancer by following a diet,” Associate Professor Crowe said.

“You don’t hear so much about people who made the same changes and died from their cancer. As far as the public are concerned, the anecdote is much more powerful than a clinical trial [a scientifically designed research study].”

This post originally appeared on ABC News.