Prediabetes used to be called impaired glucose tolerance or impaired fasting glucose. By definition, pre-diabetes is a condition where one has fasting blood sugar levels above normal (blood sugar between 100-125 mg/dl) but the blood sugar levels are not high enough to diagnose diabetes (fasting blood sugar above 126 mg/dl).

Those with prediabetes are more likely to develop Type 2 diabetes in the future for which preventive measures can be taken. Following a diet low in fat and calories, physical exercise, and weight loss (if overweight) can help prevent or delay diabetes. These preventive measures can "turn back the clock" and return elevated blood sugars to normal levels.