Eating a so-called ‘paleo diet’ might lead to rapid weight gain with particular risks for diabetics, one study suggests.

An Australian study has prompted researchers to warn about putting faith in diets with little or no scientific evidence.

Associate Professor Sof Andrikopoulos from the University of Melbourne says this type of low-carbohydrate, high-fat diet is simply not recommended.

It is especially unwise for people who are already overweight and lead sedentary lifestyles.

It is an important warning, as media hype around these diets - driven by celebrity chefs and celebrity weight-loss endorsements - are leading to more people trying diets backed by little more than enthusiastic marketing.

The team at the University of Melbourne were actually looking to test whether high-fat and low-carbohydrate foods would benefit people with pre-diabetes when they began their latest project.

They took two groups of overweight mice with pre-diabetes symptoms and put one on the low-carbohydrate, high-fat diet (LCHF), while the other group ate their normal diet.

The mice were switched from a three per cent fat diet to a 60 per cent fat diet, and their carbs were reduced to only 20 per cent.

The researchers used mice for the study, because their genetic, biological and behavioural characteristics closely resemble those of humans.

After eight weeks, the group on the LCHF gained more weight, their glucose intolerance worsened, and their insulin levels rose.

The ‘paleo diet’ group gained 15 per cent of their body weight. Their fat mass doubled from 2 per cent to almost 4 per cent.

“To put that in perspective, for a 100 kilogram person, that’s the equivalent of 15 kilograms in two months. That’s extreme weight gain,” Assoc Prof Andrikopoulos said.

“This level of weight gain will increase blood pressure and increase your risk of anxiety and depression and may cause bone issues and arthritis.

“For someone who is already overweight, this diet would only further increase blood sugar and insulin levels and could actually pre-dispose them to diabetes.

“We are told to eat zero carbs and lots of fat on the ‘paleo diet’. Our model tried to mimic that, but we didn’t see any improvements in weight or symptoms. In fact, they got worse. The bottom line is it’s not good to eat too much fat.”

Prof Andrikopoulos says the Mediterranean diet is the best for people with pre-diabetes or diabetes.

“It’s backed by evidence and is a low-refined sugar diet with healthy oils and fats from fish and extra virgin olive oil, legumes and protein.”

The full report is published in the journal Nature Nutrition & Diabetes.