Two fizzy drinks a day could double the risk of diabetes - even if they are diet versions - a Swedish study has found.

Research by the Karolinska Institute on 2,800 adults found that those who consumed at least two 200ml servings of soft drinks daily were 2.4 times as likely to suffer from a form of type 2 diabetes.

Many fizzy drinks are sold in 330ml cans, meaning that one and a half cans would be enough to double the risk.

Those who drank a litre of such drinks saw a 10-fold rise in their chance of suffering from the condition.

The increased risks were the same regardless of whether the drinks were sugary or artificially sweetened, the research published in the European Journal of Endocrinology found.

Researchers said the sugary drinks may have induced insulin resistance, triggering the cases of diabetes.

The new research examined links between soft drink consumption and diabetes Credit: Frank Augstein/AP

The artificial sweeteners in the diet drinks may stimulate and distort appetite, they said, increasing food intake, and encouraging a sweet tooth. Such sweeteners might also affect microbes in the gut leading to glucose intolerance.

The research was a retrospective study, which relied on participants to recall their diet habits.

Josefin Edwall Löfvenborg, lead author, said soft drinks might influence glucose metabolism and insulin sensitivity, leading to the increased risk of latent auto-immune diabetes, a form of type 2 diabetes.

“In this study we were surprised by the increased risk in developing autoimmune diabetes by drinking soft drinks,” he said. We next plan on investigating what could counter this risk.”

More research was needed into the impact of diet drinks he said.

It was also possible that those consuming low calorie drinks may have switched to them after a long history of drinking sugary versions, which could explain the link with diabetes, he added.

Consumers of soft drinks were likely to have a lifestyle which was less healthy overall, a factor which the study tried to adjust for.

Tam Fry, from the National Obesity Forum, said: “This is yet another warning that sweetened drinks, though appearing harmless on the surface, can...read more at Telegraph