Since Wear OS 3.0 was introduced, smartwatches running this operating system can no longer use Wear OS apps. Instead it is necessary to use the new application offered by the watch manufacturer.
For example, Samsung Galaxy Watch4/Watch5 must use the Galaxy Wearable application, Pixel Watch must use the Google Pixel Watch application, Fossil must use the Fossil Smartwatches application and the Wellness application for tracking fitness and health data.
On the Pixel Watch, health data monitoring needs to be done through the Fitbit app. Google has now confirmed that their smartwatches will not accurately count calories through the Fitbit app due to a bug.
According to Android Police, the calorie burn count on their Pixel Watch is 50% higher than the Samsung Galaxy Watch4. One of the reasons why this happens is because the user information entered on the Fitbit is not the same as what is entered on the Pixel Watch. Another problem is that the software is not very stable and with a reboot of the clock, the problem will be fixed.
As a reminder, the calorie count through a smart watch will never be 100% accurate as it is based on data entered by the user as well as the count through the software on the app and the watch.