In persons without diabetes, normal 'fasting' blood sugar levels are below 100 mg/dL; levels just prior to meals and snacks should be less than 110 mg/dL. Optimal levels are below 140 mg/dL two hours after meals and below 120 mg/dL before bed, according to Joslin Diabetes Center.
Diabetes patients have slightly different blood sugar goals, notes Joslin Diabetes Center. Fasting blood sugar levels should range from 70 to 130 mg/dL, while target levels before meals and snacks typically range from 100 to 130 mg/dL. Diabetics should aim for less than 180 mg/dL within the two hours after meals and from 90 to 150 mg/dL before retiring for the night.
Hemoglobin A1c levels are ideally less than six percent in persons without diabetes and below seven percent for patients with diabetes, according to Joslin.
Individuals with prediabetes face an increased risk of developing diabetes within 10 years, as well as increased risk of heart disease and stroke, according to the National Diabetes Information Clearinghouse. Lifestyle changes such as weight loss, consistent exercise and stopping smoking can greatly reduce the risk of developing diabetes, states WebMD. Research as of 2015 shows that reducing body weight by just 5 to10 percent is usually enough to bring blood sugar levels back to the normal range and avoid or significantly delay onset of diabetes.
Normal value ranges differ by laboratory due to the use of different measurements and test specimens, according to MedlinePlus.