Drink water only when thirsty; there is no need to force a fixed daily amount.
Original statement
اشرب الماء حين تعطش فقط — لا داعي لإجبار نفسك على شرب كميات محددة يومياً.
verbatim according to source. Translation by the project; the Arabic wording is authoritative.
Translation
Drink water only when thirsty; there is no need to force a fixed daily amount.
Origin
- Source status
- Third-party site (unofficial)
- Attribution
- Third-party site (unofficial; states it is not affiliated with Elawady)
- Origin
- https://altayybat.com/ar/
- Attribution uncertainty
- Lowest attribution level; no source video given.
- Claimed mechanism
Thirst accurately signals water needs.
- Claimed health effect
Avoiding overload of body systems with water
- Population concerned
General population
- Geographic restriction by Elawady
none found
Diverging source versions
- Source status
- Video transcript (own words)
- Attribution
- Elawady (machine transcript)
- Video
- Dr Diaa Al Awady د ضياء العوضي is live!لايف مش مهم خالص (Open source)
- Published
- 11 February 2026
- Timestamp
- not available (transcript has no timings)
- Attribution uncertainty
- Archive transcript (YouTube CC or AI-generated); no timestamps; 'published' is the date listed by the archive and may be the upload date. Live-stream transcripts can contain viewer comments read aloud; the quoted passage was checked in context to be spoken by Elawady.
- Source status
- Video transcript (own words)
- Attribution
- Elawady (machine transcript)
- Video
- الجزء الرابع من الندوة (Open source)
- Published
- 2 March 2024
- Timestamp
- not available (transcript has no timings)
- Attribution uncertainty
- Archive transcript (YouTube CC or AI-generated); no timestamps; 'published' is the date listed by the archive and may be the upload date. Live-stream transcripts can contain viewer comments read aloud; the quoted passage was checked in context to be spoken by Elawady.
Scientific assessment
Potentially true – Some evidence points in favour of the statement, but it is not sufficient for a clear judgement.
Certainty of evidence: moderate – Further research may still affect the assessment.
1. What was claimed?
Thirst alone should guide drinking.
2. What is demonstrably correct?
'No scientific studies were found in support of 8 x 8'; the osmoregulatory system maintains water balance in healthy adults (I-FAST-08).
3. What is wrong or exaggerated?
The same review emphasises that higher intakes are advisable for prevention of some diseases and in hot climates and vigorous work (I-FAST-08). In an RCT, high water intake reduced kidney stone recurrence (12/99 vs 27/100 over 5 years) (I-FAST-09).
4. What remains unclear?
Optimal intake in hot climates.
5. Which studies support it?
6. Which studies contradict it?
7. What applies to Germany and Europe?
EFSA adequate intakes for total water (2.0 L women, 2.5 L men from all sources) could not be fetched (verified: false).
8. What is known about Egypt?
Hot climate and kidney stone prevalence in Egypt make the exceptions practically important.
9. What practical conclusion is appropriate?
For healthy adults in moderate conditions thirst is a reasonable guide; in heat, with stones, in old age or illness people need to drink more deliberately.
Assessment details
- Rationale for certainty of evidence
For healthy adults in temperate climates with sedentary life, there is no evidence for '8 glasses a day' and thirst-driven intake is generally adequate (review). Exceptions are well documented: kidney stone formers benefit from high water intake (RCT), and hot climates, physical work, older age (blunted thirst), fever and diarrhoea increase needs.
- Source quality
Third-party site plus own words.
- Regional transferability
Egypt's hot climate increases water needs; transfer from temperate-climate evidence is limited.
- Individual exceptions
Kidney stones, hot climate, heavy exercise, elderly, children, illness with fluid loss, people on SGLT2 inhibitors or diuretics.
- Regional scope of the claim
- general (biological/medical)
- Last reviewed
- 25 October 2026 provisional
In plain language
There is no proof that everyone must drink eight glasses of water a day; healthy adults in a cool climate can usually rely on thirst. But in hot weather, during hard work, in old age, or for people who have had kidney stones, drinking more than thirst suggests is important.
Studies on this claim
Studies supporting the claim (1)
-
Do we need eight glasses of water a day?
Valtin H. Am J Physiol Regul Integr Comp Physiol 2002 · PMID 12376390 · DOI 10.1152/ajpregu.00365.2002Narrative reviewindependent cross-checkabstract only checkedNo proof for 8 glasses in healthy adults in mild climates, but more is needed in heat, hard work and some diseases.
Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Is there evidence for '8 x 8' glasses of water a day?
- How was the study done?
Narrative review
- How many people, animals or samples were studied?
not applicable; Healthy adults
- What was actually found?
No evidence for 8 x 8.
- How large was the observed effect?
not applicable
- What do the results mean in everyday life?
Thirst usually suffices if healthy and in mild climate.
- What are the study's limitations?
Narrative; Old
- What does it say about Elawady's specific claim?
Supports C-FAST-09; partly C-FAST-10 (no fixed high intake), with stated exceptions.
- Do the results apply to Germany and Europe?
Temperate climate applies to Germany.
- What can explicitly not be concluded from this study?
Advice for hot climates or patients.
No study in this group is marked as key.
Studies contradicting or limiting the claim (1)
-
Drinking more water to prevent kidney stones
Borghi L et al.. J Urol 1996 · PMID 8583588Randomised controlled trialindependent cross-checkabstract only checkedOver five years, stones came back in 12% of those drinking a lot vs 27% without advice.
Does the study support the specific claim? No · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
High water intake and calcium stone recurrence
- How was the study done?
Randomised prospective 5-year study
- How many people, animals or samples were studied?
199 patients; First-episode idiopathic calcium stone formers (plus 101 controls)
- What was actually found?
Recurrence halved.
- How large was the observed effect?
12% vs 27%
- What do the results mean in everyday life?
Stone formers should drink more.
- What are the study's limitations?
Not blinded; Single centre
- What does it say about Elawady's specific claim?
- Do the results apply to Germany and Europe?
Italian; directly applicable.
- What can explicitly not be concluded from this study?
Benefits in people without stones.
No study in this group is marked as key.
Studies with mixed or unclear results (0)
No studies in this group.
Regional context
Germany / EU
EFSA adequate intakes for total water (2.0 L women, 2.5 L men from all sources) could not be fetched (verified: false).
Egypt
Hot climate and kidney stone prevalence in Egypt make the exceptions practically important.
What applies in my country?
General scientific assessment
Potentially true Reasonable for healthy adults in moderate conditions, with important exceptions.
This statement concerns biological or medical relationships. The scientific assessment above applies regardless of the country; country-specific food data do not change it.
References
- "Drink at least eight glasses of water a day." Really? Is there scientific evidence for "8 x 8"?. Valtin H. Am J Physiol Regul Integr Comp Physiol 2002 · PMID 12376390 · DOI 10.1152/ajpregu.00365.2002
- Urinary volume, water and recurrences in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study.. Borghi L et al.. J Urol 1996 · PMID 8583588