A Swedish study has shown that drinking more than two sugary or artificially sweetened soft drinks per day greatly increases the risk of diabetes, .
Consuming more than two 200ml drinks more than doubled the chances of developing Type 2 diabetes, it found.
A serious soft drink habit consisting of at least five drinks boosted the likelihood of having the disease 10.5 times.
Soft drinks also increased the risk of a less common condition called Latent Autoimmune Diabetes in Adults (Lada) which shares characteristic of both Type 1 and Type 2 diabetes.
Type 1 diabetes, which requires constant insulin injections, is an autoimmune disease that wipes out insulin-producing cells in the pancreas.
The Type 2 condition which affects almost three million adults in the UK alters the way the body responds to insulin and is related to obesity and lifestyle.
Researchers from the Karolinska Institute studied levels of soft drink consumption in 2,874 Swedish adults and compared them with rates of diabetes.
"In this study we were surprised by the increased risk in developing autoimmune diabetes by drinking soft drinks," lead scientist Dr Josefin Edwall Lofvenborg said.
"We next plan on investigating what could counter this risk, such as eating fatty fish.
"We are looking into this now using data from eight different countries across Europe."
Soft drinks may increase the risk of both Type 2 diabetes and Lada by influencing glucose metabolism and insulin sensitivity, said the researchers writing in the European Journal of Endocrinology.
The study looked at relative risk - the degree by which a risk is raised from its normal level - and not "absolute" risk, the scientists pointed out.
It is estimated that one in 11 people worldwide have diabetes.
