Blood sugar levels are an important measure of type 2 diabetes control.  Your healthcare provider may recommend you check your blood glucose levels at home. Fasting blood glucose is the most common blood test.  It is usually done first thing in the morning or after at least an 8 hour fast. The normal fasting blood glucose level should be less than 100 mg/dL (5.6 mmol/L).

In type 2 diabetes, the target fasting blood glucose level is between 80-120 mg/dL (4.4-6.6 mmol/L)

The hemoglobin A1c is a test used to monitor blood sugar control. The hemoglobin A1c is measured as a percentage point and is the amount of glucose attached to the red blood cells.

The red blood cells last about 120 days, so it takes about 3 months to see a change in the A1c.

This is why it is recommended your healthcare provider check your A1c at least every three months. The goal is to maintain the A1c is less than 7%. This correlates with average blood glucose levels of 140 mg/dL  (7.7 mmol/L).

At times, the fasting blood glucose level and the A1c may not offer a complete picture. This is where the post-prandial levels are important.

The post-prandial blood sugar levels are measured 2 hours after eating. The post-prandial blood sugar levels give a good idea about how well the body handles a sugar load after a meal.

At times the fasting blood glucose may be normal, but the A1c is high. Checking the post-prandial sugars may pinpoint the problem.

The A1c is a combination of  both the fasting blood sugar levels and post-prandial levels.

If the fasting blood sugars are normal, and the A1c is high then knowing the post-prandial blood sugar levels may pinpoint the problem.

High post-prandial levels indicate uncontrolled diabetes. The post-prandial levels may also fluctuate with the type of food eaten. Foods high in sugar or simple carbohydrates, for instance, may cause the post-prandial to be higher.  You may need to check the levels at different times during the day after meals.

The post-prandial blood sugar levels may also be high if the beta cells of the pancreas are no longer able to produce enough insulin.

For a lot of people living with type 2 diabetes, checking blood sugars frequently can be uncomfortable and expensive. So here is one strategy that I recommend to my patients and clients:

  • Divide the month into odd-numbered and even-numbered days.
  • On odd-numbered days of the month, check your fasting blood sugar levels.
  • On even-numbered days, check your postprandial sugar levels.
  • Try to vary the times of the that you check your post-prandial levels. For instance on one day check the levels after breakfast, the next time after lunch. At another time after dinner.


In summary, blood glucose monitoring in type 2 diabetes is important to prevent and correct metabolic derangements and prevent associated complications.