Personal details of about 150 million users of the MyFitnessPal app have been compromised in one of the biggest hacks in history.
The app allows customers to monitor their calorie intake and measure it against the amount of exercise they are doing using a database of more than 2 million foods.
The company confirmed that the accounts were compromised in February.
The breach was not discovered until 25 March and users were informed four days later.
The data breach is the largest this year and one of the top five to date, based on the number of records compromised, according to security scorecard, a risk management consultancy.
US sportswear brand under armour said user names, email addresses and scrambled passwords were among the stolen data. However, payment card data was not affected.
It urged customers to change their passwords immediately.Please subscribe to our newsletter