High blood sugar does not necessarily mean that you have diabetes. It is a condition that occurs when your body cannot transport sugar from your blood into cells. It is when it is left unchecked that it leads to diabetes. Low blood sugar is also not good for your health.
This means that you have to be careful for your blood sugar not to go high or too low. You can only do this by managing blood sugar levels in your blood. The best level for your blood sugar should be between 75 and 150. Below 75 is too low, above 240 is too high, though, the conducive level is below 150.