Research

Energy balance

Increasing absolute drinking water intake to ≥1 liter per day is associated with significant weight loss (~2.3 kg over 12 months) in overweight women, independent of diet group, physical activity, and food energy intake.

If you are overweight and trying to lose weight, try to drink at least 1 liter (about 4 cups) of water per day, especially if you currently drink less. This simple change, particularly if it replaces sugary drinks, is associated with losing about 2.3 kg (5 lbs) over a year, regardless of which specific diet you follow or how much you exercise. It is not a magic bullet, but a robust, low-cost lever for weight loss.

ModerateSupportsMEDIUM confidence
Over 12 months, the average increase in weight loss associated with drinking ≥1 l water per day was –2.3 (0.4) kg for the study sample (all diet groups combined).
Jodi Stookey et al. · Obesity · 2008

Why this rating

Observational secondary analysis of a clinical trial; associations are robust but causal inference is limited by lack of randomization to water intake.

Source

Drinking Water Is Associated With Weight Loss in Overweight Dieting Women Independent of Diet and Activity

Jodi Stookey et al. · Obesity · 2008

DOI 10.1038/oby.2008.409

cohort · n=173Cited 176×
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DOI resolved against Crossref · corpus check 2026-06-10

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