36. You skip caffeinated beverages when you need hydration
THE RESULT: You miss out on some tasty drink options.
THE FIX: Caffeinated beverages can indeed hydrate you as well as water—provided you don’t drink them in excess. Researchers used to believe that any caffeinated beverage, like soda or coffee, had a diuretic effect, meaning you’d urinate more after drinking it, increasing your risk of dehydration. But recent research has shown this to be true only if you drink large amounts—more than 500 to 600mg per day, the equivalent of 11 diet sodas or more than 5 cups of home-brewed coffee.