Drinking coffee at lunchtime cuts people's risk of diabetes, according to a recent Brazilian study.

The result was the same for caffeinated and decaffeinated coffee, taken with or without sugar.

However, people who drank coffee at any other time of day were not able to alter significantly their risk of diabetes.

While more than 10 studies have linked increased coffee drinking to lowered type 2 diabetes risk, timing has never been considered a factor until now.

Daniela Sartorelli of the University of Sao Paulo in Ribeirao Preto, Brazil said that her team's findings strongly suggested that only coffee taken with lunch affected diabetes risk.

For the purposes of the study, the research team looked at nutritional study data on 69,532 French women between the ages of 41 and 72, who were all followed for an average of 11 years.

1,415 of the women developed type 2 diabetes during the course of the original nutrition study.

Researchers found that women who drank at least three cups of coffee a day were 27% less likely to develop diabetes than those who did not.

This made the researchers look for clues about the lives of the women who avoided diabetes by drinking coffee.

They found that women who drank more than one cup of black coffee with lunch were more than 33% less likely to develop diabetes.

The researchers said that they were uncertain whether or not black coffee and coffee with milk had the same effect upon diabetes risk, and that they did not know why the positive benefits of coffee particularly showed themselves at lunchtime.