The Best Metric to Manage Your Diabetes
Average blood sugar over seven days is our #1 metric for managing diabetes.
When you read the title, you probably thought it would be A1c because your doctor tests it every three months to see whether your diabetes is under control. But there are some limitations to the A1c, and we don't want to wait three months to see whether we are doing well.
A1c has limitations and is not always accurate.
A1c is short for Hemoglobin A1c. Other names are Glycated hemoglobin, glycosylated hemoglobin, hemoglobin A1C, or HbA1c. Going forward, I will use A1c. The value shows the percentage of your red blood cells with sugar-coated hemoglobin over the last two to three months. Following the CDC guidelines,
Normal is below 5.7%,
Prediabetes is 5.7% to 6.4%, and
Diabetes is 6.5% or above.
The general guidance for people with diabetes is to be below 7.0%, but it is also possible for those with diabetes to achieve lower values.
I mentioned limitations to the A1c. In the following situations, the A1c may be off: Pregnancy, recent or heavy blood loss, recent blood transfusion, conditions that result in insufficient red blood cells (anemias), and hemoglobin variants. Read more about it on the website of the Mayo Clinic. The CDC mentions the following cases:
Kidney failure, liver disease, or severe anemia
A less common type of hemoglobin that people of African, Mediterranean, or Southeast Asian descent and people with certain blood disorders (such as sickle cell anemia or thalassemia) may have
Certain medicines, including opioids and some HIV medications.
Blood loss or blood transfusions.
Early or late pregnancy.
Another important limitation is that you usually take the A1c test every three months, and your insurance may not pay for it if you take it more often. There are A1c tests that you buy and use at home, but it is still a limited number of times when you would use it.
Let’s talk about the average blood sugar. When you have a continuous glucose monitor (CGM), you receive your blood sugar values regularly. For example, the Dexcom G6 (or G7) gives you every five minutes the values. The Freestyle Libre (FreeStyle Libre 3) shows your blood sugar every minute.
Continuous glucose monitoring (CGM) not only helps you detect changes in your blood sugar quickly but also allows you to analyze your average blood sugar whenever you want.
The advantage is clear: You can look at your average blood sugar values whenever you want. You don’t have to wait until your doctor takes your blood, and you don’t have to use A1c home tests. Another good thing: Based on your average values, you can estimate your A1c. Here is the conversion table from the Mayo Clinic:
A1C level, Estimated average blood sugar (glucose) level
6%, 126 mg/dL (7 mmol/L)
7%, 154 mg/dL (8.6 mmol/L)
8%, 183 mg/dL (10.2 mmol/L)
9%, 212 mg/dL (11.8 mmol/L)
10%, 240 mg/dL (13.4 mmol/L)
11%, 269 mg/dL (14.9 mmol/L)
12%, 298 mg/dL (16.5 mmol/L)
Analyze your average blood sugar together with the standard variation.
When you look at your reports of the average blood sugar, you will find the standard variation with many CGM, which is how much your blood sugar values rise and fall. Another word for it is glycemic variability. The lower the value, the fewer significant ups and downs you have from the average value. There are usually multiple averages: 2 days, 7 days, 14 days, 30 days, and 90 days. We propose using the 7-day average because you will see changes more quickly than with the 30 or 90 days.
If you don’t have a continuous glucose monitoring (CGM) system, continue focusing on the A1c.
You can take a look at your average values also when you use a blood sugar meter where you test a few times per day, but there are not enough values to make the analysis as reliable as with a CGM, where you have every minute or every five minutes a value. In such a case, keeping the A1c as the guiding indicator is better.
Keep analyzing your blood sugar values, and you will see that you also improve them.
Follow our guidance and combine a low-carb diet with low-intensity workouts and mindful living.
You will achieve better average blood sugar values and a lower A1c. You will also be fit, look great, and have a long life.
