If you mean the calories burned counter on your fitbit, that is your estimated calories burned that is determined by the information you imputed when you set up your device and it changes during the day by the amount of time you spend in different heart rate zones and your natural estimated daily metabolism.
So by your weight,age it sets a daily basic metabolic base line even if you aren't even wearing the fitbit.
Somewhere around 2000 usually. You'll see it ticking up by itself even if you are sedentary.
Then this rate increases as you exercise and increase your heart rate into the fat burning level and beyond while wearing it.
To lose weight you have to eat less calories than the total burned . It's called a caloric deficit.The bigger the deficit the faster you will theoretically lose weight.
So if you burn 2500 calories in 24 hours you should eat maybe 500 less than that daily to start losing weight.
It's up to you to decide how much .
The fitbit isn't totally accurate so you might have to change the number to compensate.
Hope this is what you are asking.;-)
