Blood Sugar Fluctuations in Diabetes Management

About diabetes?

Hello Director Hsiao,
Over two months ago, I had a blood test at the hospital, and my fasting blood glucose was 130 mg/dL, with a hemoglobin A1c of 6.4%.
The doctor did not prescribe medication and advised dietary control instead.
I purchased a blood glucose meter and have been testing my blood sugar 3-4 times daily while also managing my diet and losing weight; I currently weigh 84 kg (down from 102 kg).
Occasionally, my postprandial blood glucose readings are between 140-150 mg/dL.
This morning, my fasting blood glucose was 115 mg/dL (after fasting for 17 hours), which is higher than last night's postprandial reading of 107 mg/dL.
I've noticed that fasting for more than 12 hours seems to result in higher blood glucose levels compared to fasting for 8-12 hours.
Could you please explain why this might be the case?
Here are my blood glucose readings from the past 10 days:
- 5th: (pre-breakfast) 92, (post-lunch, 60 min) 135, (120 min) 98
- 6th: (pre-breakfast) 91, (post-breakfast) 114, (post-dinner) 100
- 7th: (pre-breakfast) 92, (post-lunch) 130, (pre-dinner) 95, (post-dinner) 107
- 8th: (pre-breakfast) 94, (post-breakfast) 105, (post-dinner) 123
- 9th: (pre-breakfast) 96, (post-breakfast) 116, (post-lunch) 107, (post-dinner) 126
- 10th: (pre-breakfast) 91, (post-lunch) 99, (post-dinner) 101
- 11th: (pre-breakfast) 88, (post-lunch) 104, (post-dinner) 105
- 12th: (pre-breakfast) 78, (post-breakfast) 91, (post-lunch) 124, (post-dinner) 82
- 13th: (pre-breakfast) 91, (post-lunch) 128, (post-dinner) 107
- 14th: (pre-breakfast) 115
All pre-breakfast readings were after fasting for more than 12 hours, and postprandial readings were taken 2 hours after meals.
Additionally, I have a history of hypertension, hyperlipidemia, proteinuria, and grade 5 fatty liver due to hepatitis B.
Thank you, Director Hsiao, for taking the time to respond.

Dadi Shu, 40~49 year old female. Ask Date: 2014/11/14

Dr. Xiao Yongxun reply Internal Medicine

1.
Generally, a fasting blood glucose level of 126 mg/dL corresponds to a glycated hemoglobin (HbA1c) level of approximately 6.5%.
Therefore, the test results from two months ago should be reliable.

2.
In the classification of diabetes, type 2 diabetes accounts for about 92-95% of all diabetes cases.
Its pathophysiology is related to familial predisposition and genetics, initially characterized by insulin resistance and hyperinsulinemia, followed by abnormal blood glucose levels, impaired glucose tolerance tests, pancreatic beta-cell failure, and ultimately the onset of type 2 diabetes.
Your weight has decreased from 102 kg to 84 kg over approximately 10 weeks, averaging a loss of 1.8 kg per week, which is significantly faster than the typically recommended rate of 0.5 kg per week.
It is important to ensure adequate sleep, slow down your eating pace, chew thoroughly, and aim for 80% fullness at each meal; avoid late-night snacks or overeating at dinner.
Additionally, avoid foods containing trans fats (such as butter, shortening, instant coffee mixes, and milk tea) and high fructose corn syrup (found in sugary beverages like soda), as these are high in calories but do not provide satiety, making weight loss more difficult and increasing the risk of fatty liver.
The concern is that rapid weight loss may lead to rebound weight gain.
In fact, during the weight loss process, the body's metabolic patterns and rates are also adjusting; losing weight too quickly may lead to an inability for the body to adapt, resulting in rebound weight gain, which can be detrimental to health.
3.
When weight decreases, the severity of hypertension, hyperlipidemia, proteinuria, and fatty liver should theoretically improve to varying degrees.
For example, blood pressure levels typically begin to decrease with a weight loss of 4-5 kg or more.
4.
After dinner, your blood glucose was 107 mg/dL, and after fasting for 17 hours, it was 115 mg/dL.
The difference in microvascular blood glucose readings from the glucose meter is not significant, and I believe it is not a major concern.
Of course, it is also possible that prolonged fasting has increased sympathetic nervous system activity and elevated adrenaline levels, which could raise blood glucose levels.
However, your consistent blood glucose monitoring over ten days has shown good results, so there is no need for excessive worry.
Long-term blood glucose performance and HbA1c levels are what truly matter.
5.
Dietary control, regular exercise, and lifestyle changes remain the most effective methods for managing hyperglycemia; there is no royal road.
Additionally, I encourage you to maintain good communication and discussions with your family physician.
6.
I apologize for any delays in response due to the possibility of accidentally deleting emails amidst a high volume of correspondence.

Reply Date: 2014/11/14

More Info

Managing diabetes effectively requires a comprehensive understanding of blood sugar fluctuations and the factors that influence them. Based on your recent blood sugar readings and medical history, it appears that you are actively monitoring your condition, which is a crucial step in diabetes management. Let's break down your concerns regarding blood sugar fluctuations, particularly focusing on fasting blood sugar levels and postprandial (after meal) readings.

Understanding Blood Sugar Fluctuations
1. Fasting Blood Sugar Levels: Your observation that fasting blood sugar levels can vary depending on the duration of fasting is valid. Typically, fasting blood sugar is measured after an overnight fast of at least 8 hours. However, extending this fasting period to 12-17 hours can sometimes lead to higher readings. This phenomenon can occur due to several reasons:
- Gluconeogenesis: The liver produces glucose from non-carbohydrate sources during prolonged fasting, which can elevate blood sugar levels.

- Hormonal Fluctuations: Hormones such as cortisol and glucagon can increase during fasting, promoting glucose release from the liver.

- Dawn Phenomenon: This is a natural increase in blood sugar that occurs in the early morning hours due to hormonal changes, which can affect fasting readings.

2. Postprandial Blood Sugar Levels: Your post-meal readings of 140-150 mg/dL are within the range that indicates a potential for impaired glucose tolerance, especially if they occur frequently. The American Diabetes Association suggests that postprandial blood sugar should ideally be below 180 mg/dL two hours after eating. However, consistently high readings may indicate that your body is struggling to manage glucose effectively, which could be a sign of prediabetes or diabetes.

Dietary and Lifestyle Management
Given your commitment to dietary control and weight loss, it’s essential to continue focusing on a balanced diet that emphasizes whole foods, fiber, and low glycemic index carbohydrates. Here are some strategies to consider:
- Carbohydrate Monitoring: Keep track of your carbohydrate intake, especially refined sugars and starches, which can cause rapid spikes in blood sugar.

- Regular Meals: Eating smaller, more frequent meals can help maintain stable blood sugar levels throughout the day.

- Physical Activity: Regular exercise is crucial. Aim for at least 150 minutes of moderate aerobic activity each week, combined with strength training exercises. Physical activity helps improve insulin sensitivity and can lower blood sugar levels.

Regular Monitoring and Consultation
You are already using a blood glucose meter to monitor your levels, which is excellent. Continue to track your readings consistently, as this data can help you and your healthcare provider make informed decisions about your management plan.
- Consult Your Healthcare Provider: Regular check-ins with your healthcare provider are essential, especially since you have other health conditions such as hypertension and fatty liver disease. They can help adjust your management plan based on your blood sugar patterns and overall health.

Conclusion
In summary, fluctuations in blood sugar levels can be influenced by various factors, including fasting duration, dietary choices, and physical activity. Your proactive approach to monitoring and managing your blood sugar is commendable. Continue to focus on a balanced diet, regular exercise, and consistent monitoring. If you notice persistent high readings or any concerning symptoms, do not hesitate to reach out to your healthcare provider for further evaluation and guidance.

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