@Patjen -
Only when it syncs. And I'm not sure "eat up" is fair. "Use" yes, eat up I personally don't think so. There isn't that much data being passed. I have all day sync turned on, which means I sync a minimum of 96 times a day, probably closer to 150 as the device syncs every time I open the app. I also message a fair amount. And I browse the web occasionally. I just checked my phone's data usage - 1.08 GB and the billing period ends tomorrow.
The act of syncing action is a two part action. You can even watch the two phases in action.
When the app syncs, a blue progress bar can be seen towards the top of the screen. It first paints about 5% of the bar while it connect to the device. The blue bar quickly progresses to the halfway point and the app's dashboard is refreshed. After that the app connects to the Fitbit servers, pausing at the halfway point while that happens. Once connected to Fitbit the progress bar continues until the sync is complete.
You can tell when the data connection is being used. When the bar is about to hit 50%, look at the top where the wifi/4G symbol is. There will be a spinning circle next to it when the data connection is being used.
RETIRED Enterprise Computing / "IT Guy" - Southern California - Marine Staff Sergeant 1970-78
Apple Watch 6 - iPhone 8 (iOS 16.7.8) - FitBit app 4.20 - MacBook Air (macOS Catalina)
