A popular app for monitoring weight and calories MyFitnessPal (a child project Under Armour) reported on a massive leak of data of its users. This was stated by the administration service on its official website.
According to Under Armour, a leak was discovered March 25. In February unknown was able to access user data with MyFitnessPal. To protect personal information, the service advises all its customers to change the password on the account, and experts are addressing the consequences of the leak and finding the perpetrators.
Compromised data includes email addresses, user names and passwords in encrypted form. While personal information, like credit card numbers and social security number (for US) was not at risk because it is stored on third party servers.
So if you use MyFitnessPal and I am not afraid that someone will recognize your weight a month ago, you can just change the password and continue to enter data about calories as before. That leak, of course, frustrating, but Apple has nothing to do with the way some services store user information.