Research records
Historical source snapshot. Not freshly verified, not a recommendation. Study findings, community accounts and app defaults are not interchangeable.
Publication suitability · 2026-10-15: Historical reference only; not a clinical verification. Clinical, regulatory, efficacy, safety and dose claims are not independently established by this review.
Extended fast
A fast beyond 24 hours. Electrolytes and refeeding become the practical concerns as duration grows.
Evidence category: Clinical study. This describes the source category, not approval or certainty.
Regulatory statement in source: Not separately recorded; do not infer approval from the evidence category.
An observational study of 1,422 people in a supervised multi-day fasting programme reported falls in weight, waist circumference and blood pressure, better blood lipids and glucose control, and adverse effects in under 1% of participants. Most reported no hunger after the first days, and 84% of those with existing complaints said these improved. A narrative review of human trials adds that prolonged fasting causes moderate weight loss, of which about two-thirds is lean mass, and that metabolic gains faded a few months after refeeding. Reported problems include metabolic acidosis, headache and insomnia.
Benefits reported in the imported source
- An observational programme in 1,422 people reported lower weight and pressure, better lipids and glucose.
- Adverse effects were reported in under 1% of that supervised group.
Risks and limits
- About two-thirds of the weight lost was lean mass.
- A few months after normal eating resumed, no metabolic benefit remained.
- Reported problems include metabolic acidosis, headache and insomnia.
Source bottom line: Supervised multi-day fasting lowered weight and blood pressure, but much of the loss was lean mass and gains faded.
Uncertainty: Reference information only. Not medical advice.
Study protocols — reports, not instructions
1,422 people in a supervised fasting programme at a specialist clinic
- Reported regimen
- Buchinger fasting on 200-250 kcal a day with a moderate-intensity lifestyle programme and daily medical monitoring
- Duration
- fasting periods of 5, 10, 15 or 20 days (each plus or minus 2 days)
- Reported outcome
- Weight fell 3.2 kg at 5 days to 8.6 kg at 20 days, blood pressure dropped, 93.2% reported no hunger, and under 1% had adverse effects.
- Source
- Safety, health improvement and well-being during a 4 to 21-day fasting period in an observational study including 1422 subjects (availability check 2026-10-15: possible access barrier; not independently inspected; HTTP 200)
Claim provenance
evidence.json#/catalog:food-protocol:extended-fast/protocols/0
adults in human trials of prolonged fasting, as summarised by the review
- Reported regimen
- prolonged fasting: little or no food or caloric drink, across the trials the review covered
- Duration
- 5-20 days
- Reported outcome
- Weight fell 2-10%, about two-thirds of it lean mass; blood pressure fell; 3-4 months after the fast no metabolic benefit remained.
- Source
- Efficacy and safety of prolonged water fasting: a narrative review of human trials (Ezpeleta et al. 2024)
Claim provenance
evidence.json#/catalog:food-protocol:extended-fast/protocols/1
Community and practice descriptions
Accounts of a practice are not evidence of safety or effectiveness. Words such as “standard”, “safe” or “recommended” describe the source account, not verified consensus or this wiki’s advice. Commercial and self-published citations are retained for traceability, not vendor endorsement or independent clinical corroboration.
Historical research outcome: no-verified-description · 2026-10-06
No suitable community description was independently verified in these checks. The entry remains empty; this does not establish that no practice exists elsewhere. The proposed source is a commercial fasting clinic's promotional page; its supporting excerpt makes benefit claims rather than independently documenting the proposed community routine.
- https://www.healthpromoting.com/about-water-only-fasting: no-practice-description — The proposed source is a commercial fasting clinic's promotional page; its supporting excerpt makes benefit claims rather than independently documenting the proposed community routine.
Pharmacokinetic context
No half-life recorded in this source snapshot. No value has been inferred.
Source references
- Safety, health improvement and well-being during a 4 to 21-day fasting period in an observational study including 1422 subjects (availability check 2026-10-15: possible access barrier; not independently inspected; HTTP 200)
- Efficacy and safety of prolonged water fasting: a narrative review of human trials (Ezpeleta et al. 2024)
- PubMed: prolonged fasting (availability check 2026-10-15: possible access barrier; not independently inspected; HTTP 200)
Snapshot provenance
Source ID: catalog:food-protocol:extended-fast. Commit: adc7684614f9439b41d91a3312b62e7982c7e20e. Review state: historical-not-reverified. Authored links are retained separately from the canonical evidence links in the public data. App templates/defaults and rejected drafts are archived, not deployed.
Related entries and components
None listed.