Added sugars, particularly those containing fructose, are a principal driver of diabetes and pre-diabetes, even more so than other carbohydrates, a new study has warned.

"At current levels, added-sugar consumption, and added-fructose consumption in particular, are fuelling a worsening epidemic of type 2 diabetes," said lead author James J DiNicolantonio, a cardiovascular research scientist at Saint Luke’s Mid America Heart Institute, Kansas City.

DiNicolantonio and team writing in the journal Mayo Clinic Proceedings challenge current dietary guidelines that allow up to 25 per cent of total daily calories as added sugars, and propose drastic reductions in the amount of added sugar, and especially added fructose, people consume.

The net result of excess consumption of added fructose is derangement of both overall metabolism and global insulin resistance, researchers said.

Other dietary sugars not containing fructose seem to be less detrimental in these respects.

Indeed, several clinical trials have shown that compared to glucose or starch, isocaloric exchange with fructose or sucrose leads to increases in fasting insulin, fasting glucose, and the insulin/glucose responses to a sucrose load, researchers added.

"This suggests that sucrose (in particular the fructose component) is more harmful compared to other carbohydrates," said DiNicolantonio.

DiNicolantonio and his co-authors examined animal experiments and human studies to come to their conclusions.

Data from recent trials suggest that replacing glucose-only starch with fructose-containing table sugar (sucrose) results in significant adverse metabolic effects.

Adverse effects are broader with increasing baseline insulin resistance and more profound with greater proportions of added fructose in the diet.

The totality of the evidence is compelling to suggest that added sugar, and especially added fructose (usually in the form of high-fructose corn syrup and table sugar), are a serious and growing public health problem, researchers said.