Interpreting Your Numbers: Understanding Your Metabolic Health

When it comes to assessing metabolic health, blood sugar alone doesn’t tell the whole story. Insulin resistance often begins years before blood glucose rises, making it crucial to look at additional markers like fasting insulin, 2-hour insulin, HOMA-IR, lipids, and inflammation markers.

Below, we break down what each test measures, what’s considered normal, and what your results might mean for your health.

Fasting Insulin

What it measures:
Fasting insulin reflects how much insulin your pancreas produces after an overnight fast. It’s one of the most sensitive early indicators of insulin resistance.

Normal Range:
Below 8 mIU/mL (Ideal is 3-8 mIU/mL)

What it means:

• Below 3 mIU/mL – Could indicate low insulin production, which may be seen in late-stage type 2 diabetes or type 1 diabetes.
• 3-8 mIU/mL – Optimal range, suggesting healthy insulin function.
• Above 8 mIU/mL – Indicates insulin resistance, with the pancreas overproducing insulin to compensate.

Fasting Glucose

What it measures:
Fasting glucose is your blood sugar level after at least 8 hours without food. It helps determine how well your body manages glucose.

Normal Range:
70-90 mg/dL

What it means:

• 70-90 mg/dL – Ideal range, suggesting good glucose control.
• 90-100 mg/dL – Borderline; may indicate early insulin resistance.
• 100-125 mg/dL – Prediabetes.
• 126 mg/dL or higher – Diagnostic for type 2 diabetes.

2-Hour Insulin (Oral Glucose Tolerance Test with Insulin)

What it measures:
This test measures how much insulin your body releases in response to a glucose load (usually 75g of glucose). It helps determine if your pancreas is overproducing insulin.

Normal Range:
Below 50 mIU/mL at 2 hours

What it means:

• Below 30 mIU/mL – Ideal insulin response, indicating good insulin sensitivity.
• 30-50 mIU/mL – Borderline; may indicate mild insulin resistance.
• Above 50 mIU/mL – Suggests significant insulin resistance.
• Above 100 mIU/mL – Severe insulin resistance; pancreas is working overtime.

2-Hour Glucose (Oral Glucose Tolerance Test with Glucose)

What it measures:
Blood glucose levels 2 hours after consuming a glucose drink. This test helps identify impaired glucose tolerance and prediabetes.

Normal Range:
Below 120 mg/dL

What it means:

• Below 70 mg/dL – Could indicate hypoglycemia (low blood sugar), which may result from excessive insulin secretion, especially in those with insulin resistance or PCOS.
• Below 100 mg/dL – Ideal glucose clearance.
• 100-120 mg/dL – Borderline, suggesting mild glucose intolerance.
• 120-140 mg/dL – Impaired glucose tolerance (prediabetes).
• Above 140 mg/dL – Diagnostic for diabetes.

HOMA-IR (Homeostatic Model Assessment of Insulin Resistance)

What it measures:
HOMA-IR is an equation that estimates insulin resistance based on fasting glucose and fasting insulin.

Normal Range:
Below 1.9

What it means:

• Below 1.0 – Optimal insulin sensitivity.
• 1.0-1.9 – Normal range, though the lower, the better.
• 2.0-2.9 – Moderate insulin resistance.
• Above 3.0 – Significant insulin resistance.

(Formula: Fasting Insulin (mIU/mL) × Fasting Glucose (mg/dL) ÷ 405 = HOMA-IR)

Hemoglobin A1c (A1c)

What it measures:
A1c provides an average blood sugar level over the past 2-3 months by measuring the percentage of glycated hemoglobin in red blood cells.

Normal Range:
Below 5.7%

What it means:

• Below 5.2% – Optimal, suggesting excellent glucose control and low insulin levels.
• 5.2 – 5.6% – Normal, but may still indicate early insulin resistance, particularly if insulin levels are elevated.
• 5.7 – 6.4% – Prediabetes, signaling significant insulin resistance.
• 6.5% or higher – Diabetes, diagnostic for type 2 diabetes.

While most healthcare providers consider anything below 5.7% as normal, early metabolic dysfunction can start in the mid-5s, especially if fasting insulin or 2-hour insulin is elevated. This is why testing insulin along with A1c provides a clearer picture of metabolic health.

Lipid Panel (Cholesterol & Triglycerides)

What it measures:
Lipids give insight into heart health and metabolic function. Insulin resistance often worsens cholesterol profiles.

Normal Ranges:

• Total Cholesterol: Below 200 mg/dL
• LDL (“bad” cholesterol): Below 100 mg/dL
• HDL (“good” cholesterol): Above 50 mg/dL for women, above 40 mg/dL for men
• Triglycerides: Below 100 mg/dL
• Triglyceride to HDL ratio (TG/HDL): Below 1.5 is optimal, while a ratio above 2.9 may indicate insulin resistance and an increased risk of cardiovascular disease.

C-Peptide

What it measures:
C-peptide is a byproduct of insulin production. Since it’s not cleared by the liver like insulin, it can provide a clearer picture of insulin secretion.

Normal Range:
0.5-2.0 ng/mL

C-Reactive Protein (CRP)

What it measures:
CRP is a marker of systemic inflammation, which is commonly elevated in insulin resistance and metabolic syndrome.

Normal Range:
Below 1.0 mg/L

Alanine Aminotransferase (ALT)

What it measures:
ALT is a liver enzyme that helps assess liver health. Elevated ALT levels may indicate fatty liver disease, which is strongly linked to insulin resistance.

Normal Range:
Below 30 U/L

What it means:

• Below 20 U/L – Optimal liver function.
• 20-30 U/L – Borderline, may indicate early metabolic dysfunction.
• Above 30 U/L – Can indicate fatty liver or liver stress related to insulin resistance.

How Often Should You Test These Markers?

• If you’re starting a Low Insulin Lifestyle: Test every other month until levels normalize.
• Once your levels are in the normal range: Testing annually is recommended for long-term monitoring.
• For those with high insulin or metabolic dysfunction: More frequent monitoring may be needed, especially if making lifestyle changes.

Final Thoughts

Interpreting lab results gives you the power to take control of your metabolic health. By focusing on insulin, glucose, lipids, liver health, and inflammation markers, you can detect issues early and make informed decisions to improve overall health.