“Eight glasses a day? That actually was not based on good science,” says Dr. Steven Willey, an internal medicine specialist. “It was based, decades ago, on the idea that you should take in a certain amount of water per calorie ingested. It turns out that we do need a good amount of liquid: 100 ounces for men, 72 ounces for women. But that includes the liquid in foods, and the rest doesn’t have to be all water. Another myth is that because tea and coffee have caffeine, they don’t count.” Even fruits and vegetables, such as watermelon and cucumber, can contribute.
So how do you know you’re drinking enough? If you’re rarely thirsty and your urine is colorless or pale, says the Mayo Clinic. As much as 60 percent of our body weight is water, and it only takes a 1 to 2 percent drop to cause dehydration.
“A lot of us walk around dehydrated—our skin itchy and flaky, our throats parched, and our noses bleeding—when we’re breathing winter’s forced air,” says Rabia Rahman, instructor in nutrition and dietetics at Saint Louis University. Most of us don’t drink enough to cleanse ourselves of toxins, she adds.
Water in plastic bottles adds its own toxins. Plasticides leach out, especially if the bottle’s been sitting in the sun, waiting in a warm car, or stuck in the freezer. These phthalates mimic estrogen and have been linked to all sorts of reproductive, immunological, and cancerous conditions.
So does tap water need to be filtered? It depends. Last year, researchers tested water in 25 municipalities. In one-third of the water supplies, they found traces of unregulated contaminants—18, all told, including 11 perfluorinated compounds, an herbicide, two solvents, caffeine, an antibacterial compound, a metal, and an antidepressant. If your water’s that laden, filter it.
If you’re drinking glass-bottled water, wean yourself from added sugars or artificial sweeteners, Rahman suggests. Try slices of lemon, orange, or lime; float strawberries or raspberries in the water bottle; add cucumber slices or crushed peppermint leaves. “I don’t think you need to spend extra money on vitamin water,” she says, “unless that’s the only way you’re going to drink the water.”
As for the frequent trips to the loo, Rahman shrugs apologetically: “It’s worth it.”