New research points to added sugars, especially fructose, as the main driver behind the development of diabetes and pre-diabetes.

Current dietary guidelines allow 25 percent of total calories to include added sugars, but these new findings suggest the need for a drastic reduction in added sugar consumption.

"At current levels, added-sugar consumption, and added-fructose consumption in particular, are fueling 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 in Kansas City, Mo. "Approximately 40 percent of U.S. adults already have some degree of insulin resistance with projections that nearly the same percentage will eventually develop frank diabetes."

The recent findings suggest consuming added fructose influences both overall metabolism and insulin resistance. Past studies have shown isocaloric exchange with fructose or sucrose leads to increases in fasting insulin, fasting glucose, and the insulin/glucose responses.

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

The recent findings revealed replacing glucose-only starch with fructose-containing table sugar led to harmful metabolic effects such as increased insulin resistance. Fructose is found naturally in some foods such as fruits and vegetables, but consuming these foods could actually help prevent against diabetes. The researchers suggest the current dietary guidelines should be modified in order to encourage people to choose whole fruits and vegetables over processed food with added sugar.