A new study has found that people who wolf down their food are twice at increased risk of developing impaired glucose tolerance, known as pre-diabetes.
The increase was not seen in people with other eating patterns, including snacking and late-night eating.
Type 2 diabetes is caused when not enough insulin - which converts blood glucose into energy in cells - is produced for the body to function properly.
In those with impaired glucose tolerance (IGT), blood glucose levels are higher than usual, but not high enough to cause diabetes.
However, it can progress to type 2 diabetes if preventative steps are not taken.
In the Japanese study - after taking into account weight, sex, age, family history of diabetes, smoking and alcohol intake, blood pressure and cholesterol - fast eating was the only pattern that significantly increased the risk for development of IGT, reports the Daily Mail.
One theory is that eating quickly increases postprandial blood glucose, the amount of sugar in the blood soon after eating.