8 Myths About How Coffee Affects Your Health—and the Truth You Need to Know

Will I get dehydrated from drinking coffee?

This is the biggest coffee myth, experts agree. When British researchers studied the body fluid levels of 50 men, they were the same whether the men drank coffee or water for hydration. “We tell people to drink eight 8-oz cups of fluid per day, and we always thought you couldn’t include coffee,” says Halle Saperstein, RD, of Henry Ford West Bloomfield Hospital in Michigan. “But now studies show otherwise. It’s OK to count coffee as part of your fluid intake.” Watching for the signs of dehydration is a much better indicator than cutting out coffee altogether. This is really what happens to your body when you have coffee every day.

So why the myth? “Caffeine is a natural diuretic, but the amount that you urinate is not as significant as we once believed,” says Saperstein. Still, since too much caffeinated coffee can make you jittery, water is probably the best form of hydration. Drink coffee in the morning, and use plain H20 for fluid intake the rest of the day.