If your breakfast usually consists of white bread and sugary cereals, you may be increasing your risk of diabetes, heart disease and possibly cancer, new Australian study finds.

Sydney researchers say they've found conclusive evidence that diets heavy in high glycemic index foods lead to a higher risk of lifestyle diseases, according to a report from Australian news agency AAP.

Nutrition experts at the University of Sydney evaluated 37 diet studies involving nearly two million people worldwide, according to the report.

The results, published in the American Journal of Clinical Nutrition, found a link between a high GI diet consisting of highly processed foods and a high risk of type 2 diabetes and heart disease. The diet was also linked to gall stones and some types of cancer.

Lead author Alan Barclay said the link with diabetes was "not surprising" because high GI foods raise blood glucose and insulin levels.

"Other research shows that a high GI diet tends to reduce good HDL cholesterol levels and raise triglycerides levels; bad news for cardiovascular diseases," he said.

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Click here to see the study.