Harvard School of Public Health researchers found that people who regularly tanked up on large amounts of coffee significantly reduced the risk of developing type 2 diabetes, compared to non-coffee drinking participants. Male coffee drinkers cut their risk by 50 per cent and female coffee drinkers reduced their risk by nearly 30 per cent.

"This is good news for coffee drinkers; however it doesn't mean everyone should run out for a latte," said Frank Hu, lead researcher and a Harvard professor of nutrition and epidemiology. "We still don't know exactly why coffee is beneficial for diabetes, and more research is clearly needed."

Decaffeinated coffee, which contains a very small amount of caffeine, was also beneficial, but its effects were weaker than those of full-octane coffee. The study noted that coffee contains antioxidants and minerals such as magnesium that may improve the effectiveness of the body's insulin and thus ward off diabetes.