“Drink eight glasses of water a day” is one of those rules everyone has heard and almost no one can trace back to an actual source. It’s not wrong, exactly — it’s just not the whole picture.
What the guidelines actually say
The Indian Council of Medical Research’s National Institute of Nutrition (ICMR-NIN), in its 2024 Dietary Guidelines for Indians, recommends around 2 litres — roughly 8 glasses — of water a day for a healthy, sedentary adult. That number moves with activity level and climate, and it rises further during pregnancy and breastfeeding, and is adjusted differently for older adults.
Harvard’s T.H. Chan School of Public Health makes a similar point from a different angle: there’s no single scientifically-proven quota that applies to everyone. Body size, how active you are, the weather, and what you eat all change how much fluid you actually need — and about a fifth of your daily water typically comes from food, not a glass at all.
So what should you actually do?
Treat 2 litres a day as a reasonable starting point if you’re a generally healthy adult in a temperate routine — then adjust upward on hot days, after exercise, or if you’re pregnant or breastfeeding. Dal, sabzi, curd, buttermilk, fruit, and tea or coffee all count toward that total; you don’t need to hit your number in plain water alone.
If you’re consistently thirsty, or your urine is dark and infrequent, that’s a more useful everyday signal than counting glasses — we cover exactly what to look for in the next article in this series.
A note on what this isn’t
This is general wellness information, not medical advice. If you have a health condition that affects fluid balance — kidney issues, heart conditions, or anything your doctor has already flagged — follow their specific guidance instead of a general guideline like this one.
