DIABETES MELLITUS is a carbohydrate intolerance disorder. Diabetes mellitus refers to a group of diseases where you have too much glucose in your blood. It results from an insulin deficiency and/or insulin resistance. Chronic diabetes conditions include type 1 diabetes and type 2 diabetes. Potentially reversible diabetes conditions include prediabetes (blood sugar levels are higher than normal, but not high enough to be classified as diabetes) and gestational diabetes (during pregnancy, but may resolve after the baby is delivered).