Answer: False. Moderate amounts of caffeine–about 300 milligrams, roughly three cups of coffee–apparently cause no harm in most healthy adults. At high levels (more than 744 milligrams per day, around seven or eight cups of coffee), caffeine may increase calcium and magnesium loss in urine. But recent studies suggest it does not increase your risk for bone loss, especially if you get enough calcium. You can offset the calcium lost from drinking one cup of coffee by adding just two tablespoons of milk.