Is Your Blood Sugar Really ‘Normal’? A Functional Perspective

That afternoon energy crash? The mood swings? The stubborn weight gain? These could all be signs of blood sugar dysregulation—long before it shows up on a lab test.

Our bodies communicate with us long before an issue appears on a lab panel. So, by the time your fasting glucose is high, things have been awry for a while already. This is why it’s so important to recognize the early symptoms and take action before metabolic dysfunction sets in.

I’ve worked with many women who feel exhausted, moody, and constantly reliant on caffeine—only to be told their fasting glucose is ‘normal.’ But when we dig deeper, looking at fasting insulin and HOMA-IR, the early signs of insulin resistance are often clear. Insulin resistance can develop for years before it shows up in glucose levels—fasting insulin often increases first, making it a key marker to check early.

Blood sugar serves as one of the most reliable predictors of metabolic and overall health, significantly impacting all of the body's functions.

Our blood sugar naturally ebbs and flows, but when those curves are too steep, we have a problem. Recognizing these fluctuations early allows for proactive steps to manage health before conditions worsen.

How Blood Sugar Imbalance Feels in Your Body

Blood sugar imbalances don’t always show up in lab tests first—but they do show up in how you feel every day. If you recognize any of these, it may be time to look deeper:

• “Hanger” and cravings

• Excessive thirst

• Fatigue, lack of energy

• Poor sleep at night or nighttime wake-ups

• Feeling tired after eating

• Brain fog, difficulty concentrating

• Weight gain or difficulty losing weight

• Mood swings, irritability

• Needing coffee or sugar for energy

• Skin breakouts

Long-Term Effects of Blood Sugar Imbalance:

• Inflammation

• Hormone dysregulation

• Gut issues

• Heart disease

• PCOS, infertility

• Insulin resistance, prediabetes, type 2 diabetes

• Skin issues (acne, eczema, psoriasis)

• Alzheimer’s disease

• Fatty liver disease

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Why Measuring Your Fasting Glucose May Not Be Enough

Doctors most commonly evaluate blood sugar balance by checking fasting glucose. While it’s an essential serum test, it doesn't paint a complete picture. It reflects just a single moment in time, and its values can be influenced by a variety of factors, including the quality and quantity of your sleep the night before, your stress levels, when and what you last ate, and more.

Here are the lab tests to ask your doctor to run at least once a year to assess your metabolic health. These tests help catch insulin resistance or prediabetes early, allowing for diet and lifestyle interventions:

🩸 Fasting glucose
🩸 HbA1C
🩸 Fasting insulin
🩸 HOMA-IR

It’s also important to analyze your results through a functional lens that looks at optimal health rather than just diagnosing disease. Conventional lab ranges only flag issues when they reach the threshold for diabetes, but subtle imbalances can be addressed long before that.

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Lab Ranges vs. Functional Ranges

Standard lab ranges aim to diagnose disease, while functional ranges help identify imbalances before they become full-blown conditions. By the time a lab flags high glucose, insulin resistance may have been developing for years.

Fasting Glucose

Fasting glucose is the standard when it comes to assessing blood sugar balance.

• Lab range: 70-100 mg/dl

• Functional range: 75-88 mg/dl

However, fasting glucose alone is often an incomplete assessment, showing just a moment in time. It works best when paired with other serum labs that provide a more accurate picture.

HbA1C

HbA1C measures the average blood glucose levels over the last 2-3 months by evaluating the glycation of hemoglobin in your red blood cells.

• Lab range:

  • <5.7% = Normal

  • 5.7 - 6.4% = Prediabetes

  • 6.5% (on 2 separate tests) = Diabetes

• Functional range: <5.5%

Fasting Insulin

Insulin helps the body manage excess glucose and lower blood sugar spikes. Over time, frequent spikes reduce insulin sensitivity, forcing the pancreas to produce more insulin.

• Lab range: 3-25 μU/mL

• Functional range: <5 μU/mL

Fasting insulin levels start increasing years before fasting glucose does, making it one of the most important markers of metabolic health.

HOMA-IR

HOMA-IR calculates insulin resistance using the formula: (fasting glucose x fasting insulin) / 405.

• Lab range:

  • <2 = Normal

  • 2 - 2.9 = Early insulin resistance

  • 3 = Significant insulin resistance

• Functional range: <1

You can request a HOMA-IR test or calculate it yourself using your fasting glucose and insulin levels.

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Simple Ways to Support Healthy Blood Sugar

Understanding your lab markers is empowering, but daily habits matter just as much. Here are a few simple ways to stabilize blood sugar and improve metabolic health:

✅ Start your day with a protein-rich breakfast (at least 20g of protein) to avoid blood sugar crashes.
✅ Pair carbohydrates with protein and healthy fats to slow glucose absorption.
✅ Prioritize movement after meals—even a short walk can significantly reduce blood sugar spikes.
✅ Manage stress—cortisol raises blood sugar, so breathwork, meditation, and mindful breaks can help.
✅ Get enough quality sleep—just one night of poor sleep can increase insulin resistance.

Your body is always communicating with you—listening to these signs and taking small, proactive steps now can help you feel your best for years to come.

In case you missed my previous article:

Thank you! ✨

A heartfelt thank you to everyone who supports my work here on Substack.

✨ P.S.

If you know someone facing health challenges related to blood sugar balance, hormonal or metabolic issues, or someone looking to take an active role in their health journey—or even someone who simply enjoys eating whole foods for better health—would you forward my Substack to them? I’d love it if you could share my page with a friend or restack it to your notes. Your support means so much to me—thank you! ✨

Stay wholesome,

Karina, CFNC