Glycated Hemoglobin: Why My Levels Increased Despite Healthy Eating

Issues related to glycated hemoglobin?

Hello, Doctor.
I am currently 35 years old, 168 cm tall, and weigh 56 kg.
I usually exercise regularly.
In the past, my meal times were irregular, and my portion sizes varied greatly.
Last year, during a health check, I found out that my fasting blood sugar was elevated (101).
Therefore, at the end of January this year, I went to Mackay Memorial Hospital in Taipei for a blood sugar test, where my fasting blood sugar was 87, and my hemoglobin A1c was 5.6.
A few days later, I returned to Mackay for a postprandial blood sugar test, which showed 106.
The doctor recommended that I consult a nutritionist at the same hospital.
The nutritionist advised me to eat regular meals with controlled portions, averaging 4 servings of carbohydrates per meal, along with vegetables and protein.
I followed this plan for three months, adhering to it about 90% of the time, although occasionally I consumed slightly more meat than recommended.
Generally, I do not eat sweets or drink sugary beverages, and I do not snack between meals.
After three months, I went to a nearby internal medicine clinic to check my fasting blood sugar and hemoglobin A1c again.
The results showed a fasting blood sugar of 85, but my hemoglobin A1c increased to 5.8 (0.2 higher than before).
I did not test my postprandial blood sugar this time.
Could you please help me understand why my values worsened after implementing these dietary controls? Thank you.

CHEN, 30~39 year old female. Ask Date: 2022/06/07

Dr. Li Jian reply Internal Medicine

When it comes to carbohydrates, try to choose those with a low glycemic index, such as whole grain rice or brown rice.
Additionally, fruit intake should not be excessive.
You may also consider the 16:8 intermittent fasting method, and then monitor for any changes afterward.

Reply Date: 2022/06/07

More Info

Understanding the increase in glycated hemoglobin (HbA1c) levels despite maintaining a healthy diet and regular exercise can be perplexing. Your situation is not uncommon, and several factors could contribute to this phenomenon.

Firstly, it is essential to understand what HbA1c represents. HbA1c is a measure of your average blood glucose levels over the past two to three months. It reflects how well your blood sugar has been controlled during that time. A level of 5.6% is generally considered normal, while a level of 5.7% to 6.4% indicates prediabetes, and 6.5% or higher suggests diabetes.

In your case, despite a decrease in fasting blood glucose from 101 mg/dL to 85 mg/dL, your HbA1c level increased from 5.6% to 5.8%. This could be attributed to several factors:
1. Glycemic Variability: While your fasting blood glucose levels are within the normal range, it is crucial to consider the variability of your blood sugar levels throughout the day. If your postprandial (after meal) blood sugar levels are significantly elevated, even if your fasting levels are normal, this can contribute to a higher HbA1c. The fact that your postprandial blood sugar was recorded at 106 mg/dL indicates that there may be spikes in your blood sugar after meals that could be influencing your overall average.

2. Diet Composition: Although you mentioned following a structured meal plan, the composition of your meals can significantly impact blood sugar levels. For instance, consuming larger portions of carbohydrates or higher glycemic index foods can lead to spikes in blood sugar, which may not be reflected in fasting levels but can affect HbA1c. It’s also important to consider the timing of your meals and how they align with your activity levels.

3. Physical Activity: While you are exercising regularly, the intensity and type of exercise can also influence your blood sugar levels. For example, if your workouts are not intense enough to lower blood sugar levels effectively, or if you are not incorporating strength training, this could affect your overall glucose metabolism.

4. Hormonal Fluctuations: Hormonal changes, such as those related to stress, sleep, or even menstrual cycles, can affect insulin sensitivity and blood sugar levels. If you have experienced any stress or changes in your routine, this could impact your glucose control.

5. Individual Variability: Each person's body responds differently to diet and exercise. Factors such as genetics, metabolic rate, and even gut microbiota can influence how your body processes carbohydrates and regulates blood sugar.

6. Measurement Variability: Laboratory tests can have variability, and it is essential to ensure that the tests are conducted under similar conditions. Factors such as hydration status, time of day, and even the specific laboratory methods used can lead to differences in results.

Given these factors, it may be beneficial to continue monitoring your blood sugar levels, particularly postprandial levels, to gain a clearer picture of your glucose control. Additionally, consider consulting with a registered dietitian or a diabetes educator who can help you fine-tune your meal plan and ensure that you are balancing carbohydrates with adequate protein and healthy fats to stabilize your blood sugar levels.

Lastly, if you continue to see fluctuations in your HbA1c despite your efforts, it may be worthwhile to discuss with your healthcare provider the possibility of further testing or evaluation for any underlying conditions that may be affecting your blood sugar regulation. Regular follow-ups and adjustments to your management plan can help you achieve better control over your blood glucose levels and overall health.

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