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“ Introducing Cronometer On Apple Watch”
The new Apple Watch app does not show an accurate calorie burn on the watch face unless you open the Cronometer app on your iPhone at the same time. Background refresh on or off it doesn’t matter. It will only show the bmr burned you start the day with or a slightly larger number but not the actual burn calories at that time. Again it will only refresh when you open the app on the phone. Even then once you close the watch app it will reset back to basic bmr burn when you reopen the app on your watch.
Edit: My wife tried it on her watch and the same thing happens with hers as well.