What could be wrong when my blood sugar stays low all the time?

Couple thoughts: In the case of blood sugar always being low lab testing needs to be done to rule out insulinoma. The most common cause of hypoglycemia (low blood sugar) however is, contrary to what one might expect, eating sugar. A sugar spike leads to an insulin spike (insulin takes sugar out of bloodstream and into cells) which often "overshoots" leading to low blood sugar. Also watch diet soda and coffee