Calories In and Calories Out/Deficit

[msclairvoyant]

Hello! I've been using my Fitbit Charge 2 for over a week now but I still have lingering questions about how the Calories In vs Out is suppose to function.

I have my food plan goal set for weight loss at 1.5 pounds a week, a 750 calorie deficit. At this moment, looking at my app, I have burnt a total of 2,447 cal and have ate 1,870 cal. Fitbit is telling me I still have 162 calories left I can eat and I'm nearing the end of the day.

My question is how does the math work on this? I've used MyFitnessPal for years before this and understood that well enough but this version, I admit, has me a little stumped. When I subtract the 1,870 from 2,447, I do not get a deficit of 750. I get 577. That will be even less if I ate the extra 162. How exactly is this operating? I've read that it's taking into account calories burned/not ate from previous days? Is that true? A thorough explanation would be really helpful because it's worrying me a little.

Thank you!

[SteveH]

The slate is wiped clean at midnight each day so no calories eaten / burned are carried forward from the previous day.

What causes confusion with the food planner is that fitbit tries to estimate where you'll be at the very end of the day rather than where you are at this point in time. It knows that you will be burning more calories between now and midnight, even if it's only your BMR calories, and takes this into account when working out how many more calories you can eat.