To link MyFitnessPal to your account, follow these steps:

1. Open the Withings App.
2. Tap the Share Tab.
3. Scroll down to 'Apps'.
4. Tap MyFitnessPal.
5. Tap Open.
6. Log in to your MyFitnessPal account.

Note: The Facebook Login for MyFitnessPal is not supported on Android at the moment. Please use your standard username (either username or email address) and password.

You can unlink your MyFitnessPal account and your Withings account anytime you want from your Share Tab.