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Diet Protocol

72-Hour Fasting Protocol

Extended fasting interval of approximately 72 hours.[2048,2158,2318, etc.]

Superscript reference numbers link to the Sources bibliography.

Strong Evidence
Metabolic HealthLongevity

Composite Rating

4.5/5

Blends evidence depth, community direction, safety friction, and completeness.

Evidence Intensity

90/100

High depth from human/RCT/meta counts

Community Direction

100

Positive Lean • confidence Low

Safety Friction

31/100

Early signal from adverse/interaction markers

Data Completeness

100%

Studies 16 • mentions 7 • links 25

Not medical advice. This product is for educational and informational purposes only. It does not diagnose, treat, cure, or prevent any disease and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions regarding a medical condition.

FDA disclaimer: These statements have not been evaluated by the Food and Drug Administration. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease. Results may vary. Not intended for use by pregnant or nursing women, individuals under 18, or those with known medical conditions without physician consultation.

If you are experiencing a medical emergency, call 911 or your local emergency number immediately.

Implementation Blueprint

Best fit: Niche advanced use cases under explicit medical oversight..[397,1155,2048, etc.]

Goal alignment: Metabolic Health, Longevity.[397,1155,2048, etc.]

Protocol Type

Diet Plan

Evidence Tier

HIGH

Best Fit

Niche advanced use cases under explicit medical oversight.

Primary Focus

Metabolic Health, Longevity

Safety and Pitfalls

  • High-risk strategy for many users; not a default recommendation pathway.[397,1155,2048, etc.]

At-A-Glance Evidence Architecture[2048,2158,2318, etc.]

Clinical Depth

Humans: 60 • RCTs: 14 • Meta: 0

Cohort / Real-World

Cohort signals: 7

Safety Markers

Adverse signals: 4 • Interactions: 0

Evidence Tracking

Freshness, trend, and study timeline for this item

Evidence Tracking

Status

New Evidence

Trend

→ Stable evidence base

Depth

60 total studies · 7 recent

Timeline

20112025

Top Signal Metrics[2048,2158,2318, etc.]

Total indexed

60

Human studies

60

Randomized trials

14

Cohort signals

7

Safety adverse signals

4

Mechanistic signals

3

Community Direction Mix[397,1155,5995]

Weighted direction score: 100 (Positive Lean)

Benefit1 (100%)
Adverse0 (0%)
No Effect0 (0%)
Mixed0 (0%)

Evidence Quality Summary[2048,2158,2318, etc.]

High when large human trial/meta/cohort volume exists for the named dietary protocol.

Total indexed

60

Human studies

60

Randomized trials

14

Cohort signals

7

Safety adverse signals

4

Mechanistic signals

3

Adherence/dropout signals

2

Meta-analyses

0

Study Type Breakdown

Distribution of evidence by study design strength

Randomized TrialsLevel 1b14
Cohort StudiesLevel 2b7
Human Studies (other)Level 3-439
All IndexedAll levels60
90

Evidence Strength: High

Composite of study volume, RCTs, and meta-analyses

Top Human Studies[2048,2158,2318, etc.]

PMID 23220077 • 2013 Nov

Randomized cross-over trial of short-term water-only fasting: metabolic and cardiovascular consequences.

Nutr Metab Cardiovasc Dis

Open PubMed

PMID 37862821 • 2023 Dec

The impact of prolonged fasting on 24h energy metabolism and its 24h rhythmicity in healthy, lean males: A randomized cross-over trial.

Clin Nutr

Open PubMed

PMID 39991046 • 2024

Weight loss-independent changes in human growth hormone during water-only fasting: a secondary evaluation of a randomized controlled trial.

Front Endocrinol (Lausanne)

Open PubMed

PMID 39736329 • 2025 May

Effect of 3 Different Daily Protein Intakes in a 2-Meal Eating Pattern on Protein Turnover in Middle Age and Older Adults: A Randomized Controlled Trial.

J Nutr

Open PubMed

PMID 21740575 • 2011 Jul 8

Bath Breakfast Project (BBP)--examining the role of extended daily fasting in human energy balance and associated health outcomes: study protocol for a randomised controlled trial [ISRCTN31521726].

Trials

Open PubMed

PMID 24898233 • 2014 Aug

The causal role of breakfast in energy balance and health: a randomized controlled trial in lean adults.

Am J Clin Nutr

Open PubMed

PMID 36194463 • 2022 Oct 4

Retention, Fasting Patterns, and Weight Loss With an Intermittent Fasting App: Large-Scale, 52-Week Observational Study.

JMIR Mhealth Uhealth

Open PubMed

PMID 29168341 • 2018 Jan

Introducing the 6-4-0 fasting regimen and the incidence of prolonged preoperative fasting in children.

Paediatr Anaesth

Open PubMed

PMID 34702191 • 2021 Oct 26

Quality-improvement project to reduce actual fasting times for fluids and solids before induction of anaesthesia.

BMC Anesthesiol

Open PubMed

PMID 26864365 • 2016 Mar

The causal role of breakfast in energy balance and health: a randomized controlled trial in obese adults.

Am J Clin Nutr

Open PubMed

PMID 38722043 • 2025 Jan

2D (1)H sLASER Long-TE and 3D (31)P Chemical Shift Imaging at 3 T for Monitoring Fasting-Induced Changes in Brain Tumor Tissue.

J Magn Reson Imaging

Open PubMed

PMID 33686571 • 2021 Jun

Intermittent fasting: from calories to time restriction.

Geroscience

Open PubMed

PMID 41470839 • 2025 Dec 12

Controversies and Perspectives of Time-Qualified Dietary Interventions.

Nutrients

Open PubMed

PMID 39258805 • 2024 Sep

Neuroimaging analysis reveals distinct cerebral perfusion responses to fasting-postprandial metabolic switching in Alzheimer's disease patients.

CNS Neurosci Ther

Open PubMed

PMID 39253586 • 2024

The influence of extended fasting on thyroid hormone: local and differentiated regulatory mechanisms.

Front Endocrinol (Lausanne)

Open PubMed

PMID 39033506 • 2024 Aug 27

The HuMet Repository: Watching human metabolism at work.

Cell Rep

Open PubMed

Community Report Frequency[397,1155,5995]

Benefit reports: 1

Adverse reports: 0

No-effect reports: 0

Mixed reports: 0

Unclear reports: 6

Signal confidence: 0.39

Top Reported Effects[397,1155,5995]

Benefits

  • weight loss: 1

Adverse

  • High-risk strategy for many users; not a default recommendation pathway: 1

No Effect

  • insufficient no-effect reports captured: 0

Community confidence 0.39 with mentions: benefit 1, adverse 0, no-effect 0.

Subreddit coverage: carnivorediet, fasting, keto.

Community Evidence Examples[397,1155,5995]

post • r/fasting • unclear

72 Hour Fast Experience So Far I’m currently on my last day of a 72 hour water fast and this is my thoughts and experience. 1) I feel this fast is the most easiest one I’ve done and I have attempted 72 hour fasts before. 2) I have felt gre…

Open mention

post • r/carnivorediet • unclear

Just finishing a 72 hour fast, so I can start clean on the carnivore diet. Any suggestions to my first meal which is in 3 hours? I know I’m supposed to take it a little easy.

Open mention

post • r/carnivorediet • unclear

Breaking a 72 hour fast, with high fat meal? Issues? I had the weekend to myself, and a good portion of my day is spent sitting in a treestand for hunting, so I started fasting Thursday night, and plan to refeed tonight(Sunday night), ive …

Open mention

post • r/fasting • unclear

Prolonged fasting after 40 Per Dr. Donald Layman, a PHD researcher and expert in protein metabolism and metabolic health, no one over the age of 40 should be fasting more than 36 hours and even that is not recommended because it leads to c…

Open mention

post • r/fasting • unclear

67 hours in and I can’t stop thinking of food! I am roughly 67 hours into a 72 hour fast and I cannot stop thinking of food! And I am at work! All I want to do is go grab lunch with the guys! My mental aptitude is actually pretty good! I a…

Open mention

post • r/keto • benefit

72 hour fast on keto? Hey all, I know people in here are pretty familiar with 16:8 and OMAD fasting but curious about who all has done extended 72 hour fasting on keto and what your weight loss was/how you felt doing it? (I roughly follow …

Open mention

comment • r/fasting • unclear

Serious question. Why do you do 72 hour fast? To lose a few pounds quickly and then gain it back? Are you near goal weight??

Open mention

Primary Source Links

Evidence Sources

  • https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=(%2272%20hour%20fasting%22%20OR%20%22extended%20fasting%22%20AND%20humans%5BMeSH%20Terms%5D)
  • https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=(%2272%20hour%20fasting%22%20OR%20%22extended%20fasting%22%20AND%20humans%5BMeSH%20Terms%5D)%20AND%20humans%5BMeSH%20Terms%5D
  • https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=(%2272%20hour%20fasting%22%20OR%20%22extended%20fasting%22%20AND%20humans%5BMeSH%20Terms%5D)%20AND%20humans%5BMeSH%20Terms%5D%20AND%20randomized%20controlled%20trial%5BPublication%20Type%5D
  • https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=(%2272%20hour%20fasting%22%20OR%20%22extended%20fasting%22%20AND%20humans%5BMeSH%20Terms%5D)%20AND%20humans%5BMeSH%20Terms%5D%20AND%20meta-analysis%5BPublication%20Type%5D
  • https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=(%2272%20hour%20fasting%22%20OR%20%22extended%20fasting%22%20AND%20humans%5BMeSH%20Terms%5D)%20AND%20humans%5BMeSH%20Terms%5D%20AND%20(cohort%5BTitle%2FAbstract%5D%20OR%20prospective%5BTitle%2FAbstract%5D%20OR%20longitudinal%5BTitle%2FAbstract%5D)
  • https://pubmed.ncbi.nlm.nih.gov/23220077/
  • https://pubmed.ncbi.nlm.nih.gov/37862821/
  • https://pubmed.ncbi.nlm.nih.gov/39991046/
  • https://pubmed.ncbi.nlm.nih.gov/39736329/
  • https://pubmed.ncbi.nlm.nih.gov/21740575/
  • https://pubmed.ncbi.nlm.nih.gov/24898233/
  • https://pubmed.ncbi.nlm.nih.gov/36194463/
  • https://pubmed.ncbi.nlm.nih.gov/29168341/
  • https://pubmed.ncbi.nlm.nih.gov/34702191/
  • https://pubmed.ncbi.nlm.nih.gov/26864365/
  • https://pubmed.ncbi.nlm.nih.gov/38722043/
  • https://pubmed.ncbi.nlm.nih.gov/33686571/
  • https://pubmed.ncbi.nlm.nih.gov/41470839/
  • https://pubmed.ncbi.nlm.nih.gov/39258805/
  • https://pubmed.ncbi.nlm.nih.gov/39253586/

Community Sources

  • https://old.reddit.com/search.json?raw_json=1&sort=relevance&t=year&limit=8&q=%2272%20hour%20fast%22%20(diet%20OR%20nutrition%20OR%20meals%20OR%20side%20effects%20OR%20experience%20OR%20results)%20(subreddit%3Anutrition%20OR%20subreddit%3AScientificNutrition%20OR%20subreddit%3Aloseit%20OR%20subreddit%3AMealPrepSunday%20OR%20subreddit%3Aketo%20OR%20subreddit%3Afasting%20OR%20subreddit%3Amediterraneandiet%20OR%20subreddit%3Avegan%20OR%20subreddit%3Avegetarian%20OR%20subreddit%3Acarnivorediet%20OR%20subreddit%3Abiohackers%20OR%20subreddit%3Alongevity)
  • https://old.reddit.com/r/fasting/comments/1nv7xi1/72_hour_fast_experience_so_far/.json?raw_json=1&sort=top&limit=25
  • https://www.reddit.com/search/?q=72-Hour%20Fasting%20Protocol

Scientific Evidence Notes[2048,2158,2318, etc.]

1. PubMed triage evidence summary: 72-Hour Fasting Protocol

PUBMED • Human diet protocol literature

Counts from structured PubMed protocol-specific query set.

Outcome: Humans 60, RCT 14, meta 0, cohort 7.[2048,2158,2318, etc.]

Open source
2. Randomized cross-over trial of short-term water-only fasting: metabolic and cardiovascular consequences.

PUBMED • 2013 • Human evidence curation set

PMID 23220077 from Nutr Metab Cardiovasc Dis.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
3. The impact of prolonged fasting on 24h energy metabolism and its 24h rhythmicity in healthy, lean males: A randomized cross-over trial.

PUBMED • 2023 • Human evidence curation set

PMID 37862821 from Clin Nutr.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
4. Weight loss-independent changes in human growth hormone during water-only fasting: a secondary evaluation of a randomized controlled trial.

PUBMED • 2024 • Human evidence curation set

PMID 39991046 from Front Endocrinol (Lausanne).

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
5. Effect of 3 Different Daily Protein Intakes in a 2-Meal Eating Pattern on Protein Turnover in Middle Age and Older Adults: A Randomized Controlled Trial.

PUBMED • 2025 • Human evidence curation set

PMID 39736329 from J Nutr.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
6. Bath Breakfast Project (BBP)--examining the role of extended daily fasting in human energy balance and associated health outcomes: study protocol for a randomised controlled trial [ISRCTN31521726].

PUBMED • 2011 • Human evidence curation set

PMID 21740575 from Trials.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
7. The causal role of breakfast in energy balance and health: a randomized controlled trial in lean adults.

PUBMED • 2014 • Human evidence curation set

PMID 24898233 from Am J Clin Nutr.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
8. Retention, Fasting Patterns, and Weight Loss With an Intermittent Fasting App: Large-Scale, 52-Week Observational Study.

PUBMED • 2022 • Human evidence curation set

PMID 36194463 from JMIR Mhealth Uhealth.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
9. Introducing the 6-4-0 fasting regimen and the incidence of prolonged preoperative fasting in children.

PUBMED • 2018 • Human evidence curation set

PMID 29168341 from Paediatr Anaesth.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
10. Quality-improvement project to reduce actual fasting times for fluids and solids before induction of anaesthesia.

PUBMED • 2021 • Human evidence curation set

PMID 34702191 from BMC Anesthesiol.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
11. The causal role of breakfast in energy balance and health: a randomized controlled trial in obese adults.

PUBMED • 2016 • Human evidence curation set

PMID 26864365 from Am J Clin Nutr.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
12. 2D (1)H sLASER Long-TE and 3D (31)P Chemical Shift Imaging at 3 T for Monitoring Fasting-Induced Changes in Brain Tumor Tissue.

PUBMED • 2025 • Human evidence curation set

PMID 38722043 from J Magn Reson Imaging.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
13. Intermittent fasting: from calories to time restriction.

PUBMED • 2021 • Human evidence curation set

PMID 33686571 from Geroscience.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
14. Controversies and Perspectives of Time-Qualified Dietary Interventions.

PUBMED • 2025 • Human evidence curation set

PMID 41470839 from Nutrients.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
15. Neuroimaging analysis reveals distinct cerebral perfusion responses to fasting-postprandial metabolic switching in Alzheimer's disease patients.

PUBMED • 2024 • Human evidence curation set

PMID 39258805 from CNS Neurosci Ther.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
16. The influence of extended fasting on thyroid hormone: local and differentiated regulatory mechanisms.

PUBMED • 2024 • Human evidence curation set

PMID 39253586 from Front Endocrinol (Lausanne).

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source
17. The HuMet Repository: Watching human metabolism at work.

PUBMED • 2024 • Human evidence curation set

PMID 39033506 from Cell Rep.

Outcome: See linked PubMed abstract for methods and outcomes.[2048,2158,2318, etc.]

Open source