A diabetes management system and method are provided herein that may be used to analyze a patient's level of control of their diabetes, by looking at the difference between blood glucose measurements taken before and after a meal. If the standard deviation of the differences D calculated between pre- and post-prandial results is found to vary significantly from a predetermined threshold value, then a message or graphical indication may be displayed to the user. Messages may provide suggestions to the user as to ways to better manage their condition to ensure compliance of any prescribed diabetes regimen or to guide the patient in managing their diabetes.