Systematic reviewindependent cross-checkabstract checked★ key study I-FAST-123 standard review

Trials of drinking more water

Outcomes in Randomized Clinical Trials Testing Changes in Daily Water Intake: A Systematic Review.

Overview

Hakam N et al.. JAMA Netw Open 2024 · PMID 39585691 · DOI 10.1001/jamanetworkopen.2024.47621

Only 18 trials exist; drinking more water helped with kidney stones and weight loss in some.

Does the study support the specific claim? Partly · Methodological quality: moderate

Study explained simply

What did the researchers want to find out?: Summarise RCTs of water intake.
How was the study done?: Systematic review.
How many people, animals or samples were studied?: 18 RCTs.
What was actually found?: Benefits for stones and weight in some trials.
How large was the observed effect?: 15 fewer stones per 100 over 5 years.
What do the results mean in everyday life?: No strong proof that everyone must drink a set amount; some people benefit from drinking more.
What are the study's limitations?: Few, heterogeneous trials.
What does it say about Elawady's specific claim?: Partly supports thirst-guided drinking; limits it for specific groups.
Do the results apply to Germany and Europe?: Applies; same physiology.
What can explicitly not be concluded from this study?: Optimal intake in hot climates.

Authors: Hakam N et al.
Journal: JAMA Netw Open
Year: 2024
Identifier: PMID 39585691 DOI 10.1001/jamanetworkopen.2024.47621
Verification: verified – PubMed efetch 2026-10-26; Crossref update-to/updated-by check
Retracted: no
Corrections: none
Extent checked: abstract only
Conflicts of interest and funding: not stated in abstract

What health outcomes have RCTs of changing daily water intake shown?

Results: Additional water associated with greater weight loss (44%-100% more than control) and fewer nephrolithiasis events (15 fewer per 100 over 5 years); single studies suggested benefits for migraine, UTI, diabetes control and hypotension. 10 studies (55%) at least 1 positive result; 8 (44%) negative.
Absolute risks: not reported
Authors' conclusion: Limited number of trials; small number suggest benefits of water intake on weight loss and nephrolithiasis; more well-designed studies needed.

Evidence base thin in both directions.

Shows that neither 'fixed high intake for everyone' nor 'thirst is always enough' rests on a strong trial base; some groups benefit from more water.

Universal biology; applies in Europe and Egypt.

Supports a nuanced reading: thirst is adequate for many, but extra water helps specific groups.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
Risk of bias	some concerns
Precision of results	not applicable
Directness	direct
Reproducibility	partly replicated
Consistency with the overall evidence	mixed
Regional transferability	moderate
Adequacy of the interpretation (by the archive)	not applicable