# Proof: You must wait at least 30 minutes after eating before swimming or you will suffer dangerous cramps.

- **Generated**: 2026-03-28
- **Verdict**: DISPROVED (with unverified citations)
- **Audit trail**: [proof_audit.md](proof_audit.md) | [proof.py](proof.py)

## Key Findings

- **3 of 4 independent authoritative sources** verified via live page fetch confirm that the claim is a myth with no scientific basis.
- **No peer-reviewed study** has ever documented a case of drowning caused by swimming after eating.
- **No major medical or safety organization** (American Academy of Pediatrics, American Red Cross, ILSF) recommends waiting 30 minutes after eating before swimming.
- While mild discomfort is possible during vigorous exercise after eating, medical sources characterize this as inconvenient, not dangerous.

## Claim Interpretation

**Natural language claim**: "You must wait at least 30 minutes after eating before swimming or you will suffer dangerous cramps."

**Formal interpretation**: This is a compound causal assertion: (1) swimming within 30 minutes of eating causes muscle cramps, AND (2) those cramps are dangerous (severe enough to cause drowning or serious injury). The claim is treated as a universal rule ("you must," "you will"), not a probabilistic statement. If authoritative medical sources reject either sub-claim, the overall claim is disproved.

**Disproof threshold**: >= 3 independent authoritative sources that reject the causal claim. This is the standard threshold for qualitative consensus proofs.

*Source: proof.py JSON summary*

## Evidence Summary

| ID | Fact | Verified |
|----|------|----------|
| B1 | Duke Health: myth that blood diversion causes dangerous cramps is unfounded | Yes |
| B2 | UAMS Health: no medical evidence supports the myth | Yes |
| B3 | Britannica: science does not support the food-drowning link | Yes |
| B4 | International Life Saving Federation: no evidence eating before swimming increases drowning risk | No (quote not found via Wayback — PDF source) |
| A1 | Verified source count meeting disproof threshold | Computed: 3 sources verified, meeting threshold of 3 for disproof |

*Source: proof.py JSON summary*

## Proof Logic

The claim that swimming within 30 minutes of eating causes dangerous cramps is a piece of folk wisdom with no scientific support. The disproof proceeds by collecting authoritative medical sources that explicitly reject this claim.

**Duke Health** (B1) states that the theory behind the myth — that blood diversion to the digestive tract impairs muscle function — "is unfounded." **UAMS Health** (B2) confirms "there is no medical evidence to support the myth." **Encyclopaedia Britannica** (B3) notes that "the chances of suffering a stomach cramp while swimming are remote, regardless of when the swimmer last ate," and that medical science has "long ago disputed the food-drowning link, with papers from the 1950s and beyond questioning whether there was any correlation."

The **International Life Saving Federation** (B4) published a position statement concluding that eating before swimming does not increase drowning risk, though the PDF citation could not be verified via automated fetch.

Three independently sourced and verified citations (B1, B2, B3) meet the disproof threshold of 3, confirming medical consensus rejects this claim.

*Source: author analysis*

## Counter-Evidence Search

1. **Is there any peer-reviewed study supporting the claim?** Searched across medical databases and general web. No peer-reviewed study was found. Multiple sources explicitly state that no documented case of drowning caused by swimming on a full stomach has ever been recorded in medical literature.

2. **Do any major medical or safety organizations recommend waiting?** Neither the American Academy of Pediatrics nor the American Red Cross makes any such recommendation. The ILSF explicitly states the recommendation is unfounded. The 2011 Red Cross Scientific Advisory Council review found no evidence of danger.

3. **Could strenuous competitive swimming after eating pose some risk?** Some sources note mild discomfort is possible during vigorous exercise after eating, but characterize this as inconvenient, not dangerous. No source describes exercise-associated cramps after eating as a drowning risk.

*Source: proof.py JSON summary*

## Conclusion

**DISPROVED (with unverified citations)**. The claim that you must wait at least 30 minutes after eating before swimming or suffer dangerous cramps is a myth with no scientific basis. Three verified authoritative sources (B1 Duke Health, B2 UAMS Health, B3 Britannica) independently confirm that the supposed causal mechanism is unfounded, cramps from swimming after eating are rare and not dangerous, and no drowning has ever been documented from swimming after eating. The disproof does not depend on the unverified citation (B4 ILSF PDF) — the three verified sources alone meet the threshold.

Note: 3 citation(s) come from unclassified or low-credibility sources (tier 2). Duke Health and UAMS Health are university medical system websites; their tier-2 classification reflects automated domain lookup, not actual credibility concerns — both are affiliated with accredited medical schools. See Source Credibility Assessment in the audit trail.

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Generated by [proof-engine](https://github.com/yaniv-golan/proof-engine) v0.10.0 on 2026-03-28.