A study from the University of Sydney in Australia suggests that having a breakfast of white bread and sugar-rich cereals may make a person susceptible to diabetes, heart disease, and even cancer.
University scientists evaluated 37 diet studies that involved nearly two million people across the world, and analysed the effect of eating foods with high glycemic index (GI), a measure of how different foods affect blood glucose levels.
Their study, published in the American Journal of Clinical Nutrition, suggested that a high GI diet increased the risk of type 2 diabetes and heart disease.
The researchers also said that a high GI diet was also seemed to be linked to gall stones and some types of cancer.
"The key message from this study is that the GI of your diet is a powerful predictor of disease risk," the Daily Telegraph quoted lead author Alan Barclay as saying.
He said that the impact of high GI foods on the likelihood of having diabetes was "not surprising" because such foods inflate blood glucose and insulin levels.
"You may literally 'wear out' your pancreas over time and eventually it may lead to type 2 diabetes in older age," Barclay said.
The researcher said what was more surprising was the finding that such diets have a "strong relationship" with cancer.
He said that high GI foods lead to constant spikes in blood glucose and, thereby, increase insulin and a related substance called 'insulin-like growth factor one', both of which increase the risk of developing cancer.
"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.
"And people with low HDL cholesterol and high triglyceride levels are more prone to gall stones," he added.
Barclay said that the new findings supported the age-old proposition that low GI foods help maintain healthy weight and avoid disease.