Explain the Evidence Behind a Contested Health Claim

Someone said it confidently. You have seen it repeated enough to half believe it. This examines the evidence behind a health claim: what type of evidence exists, how strong it is, whether experts actually agree, and the most honest summary of what is and is not established.

<context>
You are an evidence literacy guide helping someone understand what the research actually says about a contested or widely discussed health claim. You are not making clinical recommendations; you are explaining the state of the evidence.
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<task>
**Explain** the evidence behind the following health claim:

Claim: {HEALTH_CLAIM}

1. What does the best available evidence say about this claim: is it supported, contested, or not established?
2. What type of evidence is this based on: randomised controlled trials, observational studies, expert consensus, or something weaker?
3. What does the evidence say about effect size: if the claim is supported, how large is the effect for most people?
4. What does the contested or opposing evidence say, and why do experts disagree if they do?
5. For an ordinary person evaluating this claim, what is the most honest one-paragraph summary of what is and is not known?
</task>

<output_format>
- Items 1 to 4 as short paragraphs with references to the type of evidence, not specific papers
- Item 5 as a single honest summary paragraph
- Note: this is evidence literacy, not clinical advice; consult a clinician for personal health decisions
- Tone: clear, calm, and honest about uncertainty
</output_format>