Blood Sugar Regulation Mechanics

Blood glucose is tightly regulated by the hormones insulin and glucagon. After meals, rising blood sugar triggers insulin release from pancreatic beta cells, which signals cells to absorb glucose. Between meals, glucagon maintains glucose levels by stimulating liver glycogen breakdown. In early insulin resistance, this system compensates by producing more insulin, keeping fasting glucose normal. Only when beta cell compensation fails does fasting glucose begin to rise, which is why it is a relatively late marker of metabolic dysfunction.

1

Late Marker

Fasting glucose only rises after insulin resistance is well-established and the pancreas begins to lose its compensatory ability.

2

Dawn Phenomenon

Some people have elevated fasting glucose due to cortisol-driven liver glucose production in the early morning, not necessarily due to insulin resistance.

Optimal Fasting Glucose Benchmarks

Functional Range (Metabolic Focused) Optimal: < 90 mg/dL (some experts say < 85 mg/dL)
Standard Lab Range Standard: Normal < 100 mg/dL; Prediabetes 100-125 mg/dL; Diabetes >= 126 mg/dL

Common Questions

Is a fasting glucose of 95 mg/dL concerning?

While technically in the normal range, fasting glucose in the 90-99 range warrants investigation. Test fasting insulin and HOMA-IR to check for hidden insulin resistance.

Why is my fasting glucose higher than my post-meal glucose?

This can occur due to the dawn phenomenon, where cortisol and growth hormone released in the early morning stimulate the liver to produce glucose.