Under Armour said in a statement that it was notifying users of the application about the breach.
Founded in 2005, MyFitnessPal allows users to track their diet and exercise to determine how many calories they need to eat to meet weight loss goals. The app currently has about 225 million users, according to an Under Armour spokesperson.
The company said it became aware of the breach on March 25, and that the affected data did not include government-issued identifiers, such as Social Security numbers and driver’s license numbers. Payment card data was also not affected.
No health information, such as users’ weight and what they ate, was breached either, according to a person familiar with the matter who declined to be identified.
As a result of the data breach, the company is urging users to change their passwords and be cautious of any suspicious emails or activity.