There has been much interest in whether coffee has a negative or positive effect on the prevention of diabetes. The current body of evidence indicates that coffee consumption plays a role in preventing the onset of type 2 diabetes, although diabetes prevention is complicated and involves a range of lifestyle factors.

The majority of major studies in recent years have shown that coffee can cut diabetes risk quite significantly – by up to 30%.

What is less understood is how this works. Some experts explain that the antioxidants in coffee, specifically caffeic and chlorogenic acids, have a protective effect. It has also been theorized that coffee works to cut insulin resistance, a precursor to diabetes, by helping to ease the delivery of insulin to the body’s tissues.

In 2014, Harvard Chan School researchers found that increasing coffee consumption by more than a cup a day over a four-year period reduced type 2 diabetes risk by 11%. The same study showed that those who decreased their coffee consumption by more than a cup a day increased their type 2 diabetes risk by 17%.

Another major research study conducted in Finland and published in the Journal of the American Medical Association in 2004, showed similar results. Women who drank three to four cups daily cut their risk by 29% while men cut risk by 27%. At high rates of coffee consumption of 10 cups or more, the rates increased to 80 per cent for men and 55 per cent for women.