Myth: Drink eight to ten glasses of water a day

If You Repeat Something Often Enough it Becomes the Truth!

“The European Food Safety Authority recommends that women should drink about 1.6 litres of fluid and men should drink about 2.0 litres of fluid per day. That’s about eight glasses of 200ml each for a woman, and 10 glasses of 200ml each for a man.”

“US National Research Council (NRC) that adults should consume 1 millilitre of water for each calorie of food, which adds up to about 2.5 litres per day for men and 2 litres for women.”

There is no evidence behind the eight glasses per day myth, despite countless health magazine articles.

Physician Heinz Valtin, of Dartmouth Medical School, a kidney specialist and author of two widely used textbooks on kidney and water balance.  He strongly doubts the validity of the myth that we need to drink eight glasses of water a day.  Rather, he finds it “difficult to believe that evolution left us with a chronic water deficit that needs to be compensated by forcing high fluid intake”.

Water is of course better than drinking sugar filled soft or fizzy drinks, but if we have a relatively healthy diet without too many processed foods we probably only need a handful of glasses of water per day.  

Plenty of sources have debunked this myth: New Scientist, Guardian, Vanderbilt University and FiveThreeEight.com.

Water content of some foods

Food/serving size              Water content (oz)

Yogurt 1 cup                           5.8

Watermelon 1 cup                  5

Pineapple 1 cup                      4.5

Strawberries 1 cup                 4.5

Apple 1 medium                        4

Asparagus 6 spears

(cooked)                                      3

Banana 1 medium                  2.8

Spinach ½ cup cooked         2.8

Lettuce 3 leaves                      2.7

Broccoli ½ cup boiled          2.5