Accuracy of fitbit burn?

jeepinshawn

I have the fitbit charge, non HRm model. I have lost about 75lbs or so since march and I only have about 25lbs to go until I switch over to maintenance mode and start lifting more frequently. I have been fairly satisfied with the MFP and fitbit working together, I have negative calorie adjustments enabled, but since I am set to sedentary, I don't think I have actually ever had any. As I get closer to getting out of loosing weight mode, I am trying to track my total daily burn. Over the course of the week fitbit says I burn about 3000 calories a day. So in order to track the accuracy I totaled up how many calories I consumed for the week, how many calories fitbit says I burned, and of course how many pounds of weight I have lost. Given that a lb of fat is 3500 calories, it seems pretty easy to calculate...I end up with an extra 1500-2500 calories, meaning I'm 1/2 to 3/4 a pound heavier then fitbit calculates I should be. In other words my numbers would look like this

Fitbit burn 21,000 calories consumed 10,500 calories
lost 2.5lbs= 8750 calories
19,250 calories accounted for

1750 calories unexplained

Those aren't my exact numbers, just ones that I;m using for ease of Math. So I guess my question is when I switch to maintain mode, should I deduct extra calories everyday off the fitbit burn? Or are the extra calories not really there and I'm weighing a little heavier because of water, urine, or whatever?

WBB55

Weight loss isn't linear, you might lose that weight next week even if you ate at maintenance. You might have lost all the weight as fat, but some water retention is masking it. 1750/7 days = 250 calories per day unaccounted for. How's your logging accuracy? Do you log things like ketchup, coffee, spices?

Oh so many variables. I find my FitBit accurate to +/- 70 calories per day over the long term (long term meaning 6+ weeks, not just one individual week).

editorgrrl

I've used Fitbit + MFP for two years, and I lost & maintained without ever doing any math. Here's what worked for me:

Set your goal no higher than 1 lb. per week, and after another 5 lbs. switch to .5 lb. per week: http://www.myfitnesspal.com/account/change_goals_guided

Enable negative calorie adjustments: http://www.myfitnesspal.com/account/diary_settings

Log exercise in Fitbit rather than MFP, and log everything you eat & drink accurately & honestly.

Sync your Fitbit account with Trendweight.com (it's free) to see a moving average of your weight without the "noise" of water weight. Unlike MFP's "in five weeks" nonsense Trendweight accurately predicted when I'd reach goal, and it's made maintenance easy peasy.