Authors: Michelle, RD & Michael Xie
Reprinted with permission and providing the article link.
Many individuals practicing a low-carbohydrate diet to manage type 2 diabetes, obesity, and prediabetes have found themselves diagnosed with “severe insulin resistance” during medical examinations. This includes abnormalities in blood sugar, insulin, C-peptide levels, placing them back within the range of type 2 diabetes. Despite explanations from experts supporting ketogenic and low-carb diets (such as Professors Steve Phinney, Dr. Eric Westman, etc.), there remains skepticism, partly due to the ingrained belief that health must be proven through fair testing, a mindset challenging to overcome.
Manipulating Normal Indicators?
A recent high-quality study, titled “Carbohydrate Intake Prior to Oral Glucose Tolerance Testing,” published in May 2021 by the Journal of Endocrine Society (JES) under Oxford University Press, sheds light on concerns. The study involved young, healthy volunteers practicing a low-carb diet (below 50g per meal) before oral glucose tolerance testing (OGTT), revealing elevated postprandial blood sugar with normal fasting indicators. When participants consumed a sufficient amount of carbohydrates (>150g per day and >50g the night before the test), the second OGTT yielded entirely normal results.
Why Does This Happen?
Why can the Oral Glucose Tolerance Test (OGTT), recognized as the “gold standard” by many basic hospitals, be “manipulated”? The introduction section of this paper (which is the first paragraph of the paper) actually provides its perspective. With the emergence of glycated hemoglobin (HbA1C) as the new standard for diabetes diagnosis, the OGTT has become rare in endocrinology practice (this may not be the case in some regions of China). As the OGTT gradually falls out of favor, the importance of patient preparation before OGTT has faded from memory.
The original text mentions that decades ago, literature widely known among the previous generation of endocrinologists emphasized the importance of carbohydrate intake before OGTT. However, the experiences from decades ago have evidently faded. It turns out that before conducting the OGTT, we must fully consider the adaptability of pancreatic β-cells and peripheral tissues to glucose absorption. Ensuring adherence to the correct preparation and execution protocols is crucial to avoid influencing the results.
So, having read this far, perhaps you may ponder: Does our basic healthcare system truly have sufficient understanding and comprehension of this? Certainly, for those seeking to ensure they do not fall back into insulin resistance and diabetes through any means, this fact may not be sufficient. Therefore, the paper delves into a thorough analysis on this matter.
The study suggests that the decline in insulin’s first-phase release, leading to reduced peripheral and liver glucose intake, might be responsible for abnormal OGTT results after a low-carb diet. This loss of insulin’s first-phase release is evident in early stages of both type 1 and type 2 diabetes. However, the authors argue that low-carb diets may decrease insulin sensitivity rather than causing genuine insulin resistance or secretion loss. Studies indicate an overall reduction in insulin resistance, encompassing the liver and peripheral tissues. Additionally, some research proposes a decrease in key proteins within the insulin signaling pathway, affecting rapid glucose absorption. While low-carb diets may impact insulin sensitivity, it doesn’t necessarily lead to true insulin resistance or secretion loss.
Researchers argue that the decrease in insulin sensitivity caused by a low-carb diet is reversible. Studies indicate improvements in insulin sensitivity, including first-phase release, after discontinuing a low-carb, high-fat diet in animal models. Some findings suggest that reduced expression of key proteins in the insulin signaling pathway may be an adaptive response to prolonged glucose reduction, rather than a pathological change. Normalizing carbohydrate intake may aid in restoring insulin sensitivity and promoting glucose metabolism normalization.
How to Correctly Conduct an Oral Glucose Tolerance Test to Ensure Health?
To obtain accurate OGTT results after a low-carb diet, the following steps are recommended:
- Maintain an “unrestricted diet” (high-carb intake) for at least three days before the test, consuming over 150g of carbohydrates daily.
- Optimal meal planning involves three meals per day, each containing at least 50g of carbohydrates.
- Crucially, the last meal the night before the overnight fast should include at least 50g of carbohydrates.
- Following the World Health Organization’s (WHO) advice, a 10-16 hour overnight fast with water consumption is recommended before the test.
By adhering to these guidelines, accurate OGTT results can be ensured after a low-carb diet, preventing misinterpretations.
Does a Low-Carb Diet Truly Pose No Risks?
The impact of a low-carb diet is complex and may adversely affect insulin sensitivity and glucose metabolism. While beneficial in certain cases, the diet’s influence on insulin release and glucose metabolism may lead to physiological drawbacks, particularly a decrease in the body’s efficiency in glucose metabolism.
The issue of disruptions in sugar metabolism presents an intriguing puzzle, especially considering its association with diabetes. Are these two matters truly unrelated? Examining the metrics, it indeed appears so, leading many professionals to steadfastly hold this viewpoint. An interesting analogy might shed light on this situation – imagine a classroom where two students experience a severe decline in their Chinese language grades. The teacher categorizes them both as underperformers, contemplating expulsion. Upon investigation, it’s discovered that one student has completely given up on all subjects, particularly neglecting Chinese, while the other has invested the majority of their efforts in subjects like mathematics and science, virtually abandoning Chinese studies. How should we approach the second student?
This scenario prompts a thought-provoking question: is it fair to categorize both students in the same manner? This analogy draws a parallel to the realm of metabolism, where disturbances in sugar metabolism might not necessarily equate to a universal diabetic condition. Rather, it underscores the importance of delving into the intricacies of metabolic studies, analogous to how the teacher’s understanding of the second student’s situation required a closer examination.
Understanding this phenomenon requires a nuanced approach, appreciating the multifaceted nature of sugar metabolism and its intricate connection to diabetes. It beckons the metabolism field to embark on in-depth research, acknowledging the diverse pathways and variables that contribute to the complex web of metabolic processes.
Is a Low-Carb Diet Suitable for Me?
The suitability of a low-carb diet depends on individual health conditions and needs. It may be beneficial for specific diseases or symptoms requiring carbohydrate intake control, such as epilepsy or certain cancer patients. Additionally, individuals aiming for weight control and improved metabolic health might find benefits in a low-carb diet. However, it is crucial to note that a low-carb diet is not universally suitable, and decisions should be made based on individual health assessments, guided by healthcare professionals.
In conclusion, while a low-carb diet, especially the ketogenic diet, can be viewed as an effective tool, the tool itself doesn’t equate to inherent health. It’s essential to use the tool wisely and pursue overall health from a comprehensive perspective, involving continuous contemplation.
– The End –
Note: The authors of this article have practical experience with low-carb diets, potentially influencing their viewpoints. Readers are advised to read this article objectively, critically, and form their independent opinions.
Ref：
Klein, K. R., Walker, C. P., McFerren, A. L., Huffman, H., Frohlich, F., & Buse, J. B. (2021). Carbohydrate Intake Prior to Oral Glucose Tolerance Testing. Journal of the Endocrine Society, 5(5), bvab049–bvab049. https://doi.org/10.1210/jendso/bvab049
