The National Academies puts adequate intake at ~3.7 L/day for men and ~2.7 L/day for women — including water from food and other drinks.
Pale-yellow urine and thirst that doesn't nag = adequate hydration. Dark yellow = drink more.
Rule of thumb: half your body weight in pounds = ounces of water/day (200 lbs → 100 oz), plus more for exercise and heat.
A glass of water before meals modestly reduces intake (a Virginia Tech RCT showed ~13% fewer calories per meal for adults).
Anchor hydration to your calorie plan.
Calorie / TDEE Calculator →
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