Siri was misbehaving on my iPhone 6 plus (it would understand my requests but always fail perform the task), after reading a few articles here and there I decided that the only solution was to restore my phone.
Yesterday I backed it up on my Mac, wiped it clean and the restored it from the fresh back up.
Several hours later (after the restore it had to get back in synch with all the photos, the music, the apps, etc.) everything was back to normal, except that all my health and activity data was gone.
Turns out that health and activity data is only backed up when you are encrypting your backup on your Mac or when you are using iCloud for backups, while I had unencrypted backup on my Mac.
Now: I do appreciate the fact that Apple doesn’t want my potentially sensitive health data to sit unencrypted on any disk, but I can think several different options which would have saved my data.
Not cool Apple, not cool.