Why do the calories in my budget change when I haven't eaten or exercised

[Lollyb]

Why do the calories in my budget change when I haven't eaten or exercised

[CrystalG]

When you log your height ,weight and activity level in initially, the brain in this system adjustes to figure out what your calorie burn is to just "be alive" and live each day.

[Heybales]

Becaues you burn calories living and moving too. Sleep too, wild huh!

All the calories in your daily life that you burn, exercise or not, is your TDEE.

Your eating goal is based on eating less than that, say 500 for 1 lb weekly.

A daily changing TDEE means your daily eating goal changes too.

Even before you have exercised. 

[Lollyb]

Thank you both for your response! But fitbit is actually taking away calories in my budget... For example, at one point I had 120 calories left in my budget and a couple of hours later I had 77.... Not sure why, I didn't eat anything I also didn't "do" anything.....not sure...

[Heybales · Accepted solution]

The reason is the same, the direction is different.

As the day goes on, either based on your activity setup choice or historical view, you are planned on burning so much per hr.

You've stated you did nothing, so must have been even less than Fitbit was planning on, so it removed calories to keep that deficit in place.

Some days you may do more than it's expecting, and they'll increase.

You may have many days in a row of always doing more so it'll assume that higher level is normal - then you hit a nothing day, big adjustment down then as day goes on.

[Lollyb]

Thanks! I kinda thought that was the answer....just wasn't 100% sure!