I'm adding weight data to my user using the Google Fit REST API. The data is added successfully and can be properly retrieved using the derived:com.google.weight:com.google.android.gms:merge_weight data source.
However, none of this data is visible on the Google Fit app on Android. I restarted the app, restarted the phone, added weight data from an installed Android app (which is instantly displayed in Google Fit and accessible through the API) to force a sync, add weight data with old (2 years ago) and new (now) timestamps, etc. Nothing worked.
Is the sync just slow? Is Google Fit only displaying data coming from Android apps? Could it be that my REST client (OAuth Playground, Quickstart) has limited rights? Do I need to verify my app?
The data showed up after about an hour. The solution was patience.