Gluten free foods contain more fat, salt and sugar than their gluten-containing equivalents, and are generally more than twice has expensive, a study has found.
Researchers at the University of Hertfordshire said it was clear that gluten free (GF) products offer no nutritional advantage to regular foods and are not a healthier alternative, which may surprise many consumers.
They also found that gluten free foods were 159% more expensive than their regular counterparts.
After comparing more than 1,700 food products from Tesco, Asda, Sainsbury's, Morrisons and Ocado, they found that, with the exception of crackers, gluten free foods contained more fat, salt and sugar and also had lower fibre and protein content than their equivalents.
A GF diet is the only treatment option for those who suffer from coeliac disease but many more people in the UK and around the world avoid gluten foods as it is perceived to contribute towards a healthy lifestyle, leading to a huge increase in sales of GF foods in recent years.
But despite this increased interest, there have been limited studies in the nutritional composition of gluten free foods compared with their gluten-containing equivalents, the study authors said.
Researchers found the median total fat contents for GF brown and white bread were more than double those of regular products, while the median cost of GF brown and white bread and white and wholegrain flour was over four times the price of their equivalents.
The study, which is published in the Journal of Human Nutrition and Dietetics, also found GF products had significantly lower protein content than their regular equivalents across nine out of 10 food categories.
They warned the fact that gluten free foods were found to be more expensive could lead to those with coeliac disease to stop buying them, compromising their health.
Coeliac disease is caused by an adverse reaction to gluten and affects around one in every 100 people in the UK.
The Government is currently assessing whether to restrict the availability of gluten-free foods on prescription.
The research team conducted the study by compiling an exhaustive list of commercial GF foods from the five retailers, randomly selecting gluten-containing equivalents from the same stores, with a total of 1,724 food items from 10 food categories collected and analysed.
The products were categorised according to the following groups: brown bread, white bread, white flour, wholegrain flour, breakfast cereals, wholegrain pasta, regular pasta, pizza bases, crackers and biscuits.
Dr Rosalind Fallaize, research fellow in nutrition and dietetics at the University of Hertfordshire, said: "We found that gluten free foods were significantly more expensive than regular items, which is very concerning given the movement towards stopping gluten free prescriptions for people with coeliac disease.
"It's also clear from our research that gluten free foods don't offer any nutritional advantages over regular foods so are not a healthier alternative for people who do not require a gluten free diet."