Body stages Stage 10 of 11

120 h and beyond

Prolonged fast, supervised only

Fasts this long are studied only under medical supervision, with electrolyte monitoring and slow refeeding. Ketones plateau; blood pressure and uric acid change noticeably.

Measured in humans, ModerateBeyond the 120‑hour ceiling

In Nesteia. Reference only. No plan in Nesteia reaches it; a running fast ends itself at 120 hours.

What studies measured

Ketone plateau, uric acid peaks, refeeding-risk criteria met; studied only under medical supervision.

How it may feel

Beyond the Nesteia ceiling.

What to do

Supervised settings only.

Sources

  1. 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.
  2. Owen 1969Liver and kidney metabolism during prolonged starvation. J Clin Invest, 1969.
  3. NICE CG32Nutrition support for adults: oral nutrition support, enteral tube feeding and parenteral nutrition (CG32). NICE clinical guideline, 2006.

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.

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