Body stages Stage 9 of 11
Whole-body shift
Beyond about three days, measurable changes spread across many organ systems. This is also when electrolyte losses and blood-pressure drops need attention.
In Nesteia. Reached at 96 hours, on the supervised 96 and 120‑hour plans. The studies run to day 7; in Nesteia a running fast ends itself at the 120‑hour ceiling.
What studies measured
Over 1,000 plasma proteins change only after day 3; blood pressure falling; sodium and uric acid shifting.
How it may feel
Blood pressure may sit lower; standing up quickly can bring dizziness.
What to do
Supervised plans only. Your clinician keeps checking electrolytes; the refeed takes at least three days.
Sources
- Pietzner 2024Systemic proteome adaptions to 7-day complete caloric restriction in humans. Nat Metab, 2024.
- Wilhelmi de Toledo 2019Safety, health improvement and well-being during a 4 to 21-day fasting period in an observational study including 1422 subjects. PLoS One, 2019.
- Ogłodek 2021Is Water-Only Fasting Safe?. Glob Adv Health Med, 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.