Body stages Stage 6 of 11
36–48 h
Ketosis established
Ketones are now a major fuel. Blood sugar settles in the low-normal range rather than falling further.
What studies measured
BHB 1 to 2 mmol/L and rising; glucose low-normal; circulating monocytes already reduced from about 19 hours.
How it may feel
Steadier energy for many; some feel cold or light-headed on standing.
What to do
Stand up slowly. Check the stop card if anything feels wrong.
Sources
- Service and O'Brien 2005Increasing serum betahydroxybutyrate concentrations during the 72-hour fast: evidence against hyperinsulinemic hypoglycemia. J Clin Endocrinol Metab, 2005.
- Zauner 2000Resting energy expenditure in short-term starvation is increased as a result of an increase in serum norepinephrine. Am J Clin Nutr, 2000.
- Jordan 2019Dietary Intake Regulates the Circulating Inflammatory Monocyte Pool. Cell, 2019.
What studies measured in healthy adults, not a reading of your own body. Stop and seek help if you feel unwell; the signs to stop for are listed under Stop signs on the safety page.