Jet lag happens when you cross several time zones while traveling from west to east or vice versa. It's hard for your body to align its internal clock to a new time zone – that's why you experience all kinds of annoying symptoms, from headaches to a loss of appetite. Your meal and sleep schedules are all messed up, you feel lively at night and groggy during the day... Learn more about your ad choices. Visit megaphone.fm/adchoices