The Dish on H2O
We’ve all heard the urban diet myth that we should try to guzzle 8 glasses of water every day, not just for weight control but for overall health and hydration. You may have purchased one of those 64 oz jugs to keep track of your (8 oz x 8 glass) intake, or, like if you were like me, toted a gigantic Smart Water bottle around to class in high school. Maybe you never tried or cared and were relieved when this myth was “dispelled” by new knowledge that such an average probably over predicted people’s needs.
Not so fast.
It turns out that this myth was not quite accurate. Not, however, because it over accounts for daily water intake needs.
In fact, the Adequate Intake (AI) set for daily water consumption is 9 cups for women (ages 19-50) and 13 cups for men (ages 19-50). This number is calculated to be consumed in addition to the water that you take in by eating foods. Milk, teas, juices, and even coffee (if less than 5 cups/day are consumed) can all be counted towards this daily water intake. The only beverage that can never be counted towards water intake is alcohol. You might as well forget about counting energy drinks too. Alcohol in any amount, and caffeine-containing beverages in large amounts, contribute more to dehydration than hydration. While caloric and sweetened beverages do count towards your water intake and contribute towards hydration, unless you are trying to gain weight it is best to mostly use plain water, unsweetened tea and other sugar and calorie-free beverages as your primary sources. Liquid calories add up fast and do not trigger feelings of fullness in the way that most solid foods do.
Yes, these are still average numbers and will vary from person to person. If you are an athlete, for example you will probably need more than the average. Same goes for anyone spending extended amounts of time in the heat. When we turn the heat on in our dorms and homes and when we travel on an airplane are exposed to drier air and may also need to drink more to stay hydrated.
When water loss is very high, as it would be for example for a marathon runner, electrolytes will need to be replenished in addition to water. Keep in mind however, that unless you are exercising vigorously for at least 90 minutes you will be far better off drinking a bottle of water than a sports drink (which will most likely supply you with more sugar and electrolytes than you need and more calories than you burned.)