Body stages Stage 2 of 11
4–12 h
Early fast
Insulin has fallen to its baseline. The liver is releasing stored sugar, and already making new glucose from other sources.
What studies measured
Insulin back to baseline; gluconeogenesis already about half of glucose output, 64% averaged over the first 22 hours.
How it may feel
Hunger, if it comes, follows your usual mealtimes.
What to do
Water to thirst. If your fast began after an evening meal, most of this window is sleep.
Sources
- Rothman 1991Quantitation of hepatic glycogenolysis and gluconeogenesis in fasting humans with 13C NMR. Science, 1991.
- Deru 2021The Effects of Exercise on β-Hydroxybutyrate Concentrations over a 36-h Fast: A Randomized Crossover Study. Med Sci Sports Exerc, 2021.
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.