Fasting Blood Sugar vs Postprandial Blood Sugar: Which Should You Lower?

When glycated hemoglobin (HbA1c) levels are elevated, the question arises: should we focus on lowering fasting blood sugar or postprandial blood sugar?

Let’s explore the meanings and implications of “Fasting Blood Sugar” (FBS) and “Postprandial Blood Sugar” (PPBS) in the context of diabetes diagnosis:

1. Fasting Blood Sugar (FBS):

   • FBS refers to blood sugar levels before eating, typically measured in the morning.
   • It is influenced by physiological regulation. During the 12-hour fasting period (from dinner until breakfast), the body depletes sugars consumed during the previous day’s meals.
   • Around 7:00 AM, FBS is usually at its lowest due to hormonal mechanisms that maintain normal blood sugar levels.
   • While FBS is accurate for diagnosing diabetes, it may not be sensitive enough to detect all cases.

2. Postprandial Blood Sugar (PPBS):

   • PPBS refers to blood sugar levels 2 hours after a meal.
   • It is more sensitive for diagnosing diabetes and helps identify impaired glucose tolerance (IGT) and diabetes promptly.
   • If FBS levels are elevated, PPBS levels will also be relatively higher.

3. Glycated Hemoglobin (HbA1c):

   • HbA1c serves as the international gold standard for evaluating diabetes control.
   • Interestingly, HbA1c is influenced by both FBS and PPBS.
   • Research shows that when HbA1c is between 7.3% and 8.4%, both FBS and PPBS contribute equally to overall blood sugar levels.
   • However, when HbA1c exceeds 8.5%, FBS has a greater impact on overall blood sugar.
   • Proper FBS control is essential, but PPBS is equally crucial for achieving HbA1c targets.

If your FBS is elevated, consider the following approaches:

1. Excessive Caloric Intake: Reduce evening calorie intake or engage in exercise within 30 minutes after eating to burn excess calories.
2. Inadequate Caloric Intake: If you experience the Somogyi effect (low blood sugar at night), have a small snack before bedtime (around 10:00 PM) to prevent nocturnal hypoglycemia.

Remember, both FBS and PPBS play vital roles in diabetes management. Keep monitoring and adjusting as needed to maintain optimal blood sugar levels.