The biomarkers that track carb fasting
A handful of blood and sensor measures tell you whether carb fasting is working: fasting glucose and HbA1c track your average blood sugar, a CGM and time-in-range show your day-to-day swings, fasting insulin (HOMA-IR) gauges insulin resistance, ketones confirm you're burning fat, and a lipid panel watches your cholesterol. You don't need any of them to start.
You may feel steadier energy and fewer crashes with carb fasting. A small set of measures can show you what’s changing.
Which marker tells you what
Each row below links to a deeper page that explains the number, the healthy ranges, and how carb fasting tends to move it.
| Marker | What it tells you |
|---|---|
| Fasting glucose | Your blood sugar after an overnight fast, which gives you a simple snapshot of where you stand |
| HbA1c | Your average blood sugar over about three months, giving you the longer view |
| CGM / time-in-range | A continuous sensor showing real-time swings, and how much of the day you spend in a healthy range |
| Fasting insulin (HOMA-IR) | How hard your body is working to keep blood sugar down, which can offer an early read on insulin resistance |
| Ketones | Whether you’ve shifted into fat burning. They rise on fast days and fall when you eat carbs |
| Lipids | Your cholesterol panel. Triglycerides and HDL often improve, while LDL rises for some people |
You don’t need labs to start
None of this is a gate or a lab project. You can begin today and let the numbers catch up. If you’d rather try it first, start with the plan and read the science behind why alternating days works. The biomarkers will be here when you want to measure your response.
