Every day people around the globe drink 1.6 billion cups of coffee and around twice as many cups of tea.
They enjoy the taste and the fact that the caffeine wakes them up. But when we’re exhorted to drink six or eight glasses of water a day (a disputed figure that I’ve discussed previously), it’s usually emphasised that drinks like coffee and tea don’t count towards your daily liquid total because they’re dehydrating. Or so we’re told. What’s the evidence?