In a diabetic subject the fasting blod sugar value should be in the 110 – 140 mg/dl range, and the 2-h post meal value should be between 110 and 140 mg/dl. These values are not written in stone and should vary according to the age and the general conditions. Furthermore these are not the only values to keep under control, which will be dealt in the next sections.  We can however say that to treat diabetes checking only the blood sugare level is like driving a car looking only at the side mirror.