mfp and fitbit calorie burn accuracy

ricer8

I've lost 140lbs and realize that my burned calories would change, but lately it's all very confusing. I do like to change things up to keep from getting bored, but last week I took the same walk 4 days in a row. I finished the 7miles in about the same amount of time (give or take a minute or two) and the green and yellow bars were pretty similar each day. However, after the walk each day my fit bot calories burned seemed about the same, bit mfp was all over the place. Day 1 it said 530 day 2 225 day 3 340and day 4 282. I don't get it.

ColinsMommaOC

If you mean the fitbit adjustment to your calories on MFP, its because it is taking your whole day into account, not just the time you were walking.

shadow2soul

That's because your Fitbit adjustment isn't based on just your dedicated exercise. It looks at your whole day, sends that calorie burn to MFP and MFP gives you the portion of that calorie burn that is extra (calories above what MFP thought you would burn) as an exercise adjustment. So while you may have taken the same walk 3 days in a row, your daily activity for the rest of the day varied each day.

From another post with a similar question:

shadow2soul wrote: »

Your adjustment from Fitbit isn't based on the number of steps you take. It's based on a calorie burn comparison.

When you select an activity level on MFP, MFP estimates how much you should burn in a 24 hr period based on your stats. When you log exercise, the calorie burn for the exercise gets added to this number. With Fitbit connected, it will also send the exercise log to Fitbit, so that Fitbit can correct your full day calorie burn.

Now the adjustment on MFP is:
Fitbit calorie burn - MFP burn (based on activity level + any logged exercise) = +, - , or 0 adjustment

If you don't have negative adjustments turned on, then you should do that. Your Fitbit calorie burn is your TDEE for the day (the number you have to eat less than to lose weight). MFP adjusts it's calorie burn in the form of an exercise adjustment to match your Fitbit burn so that your deficit stays at 1lb, 2lb or whatever loss per week you selected. If negative adjustments is not enabled, then when your Fitbit calorie burn is less than what MFP expects you will get an adjustment of "0". This means that you have a smaller deficit than expected (possibly even none at all).

An easy check to see the math behind your adjustment is to:
From the App - tap your adjustment 1 and you will get taken to another screen, tap it again on the new screen to see the math

From the PC - click the little "i" next to your fitbit adjustment in your exercise diary.

XavierNusum

You fitbit is estimating your TDEE or total daily energy expenditure from ALL of the activity you did that day. If that burn is more than what MFP thought you'd burn based on info you gave, then it will adjust your calories up to keep you at the predetermined deficit or weight loss goal (i.e 1lb/week). So, like the other posters said, it's not calculating the calories burned from your walk differently, but you have a different OVERALL calorie burn for that day which includes the walk.

nyponbell

Which is why, at the end of the day, your "calories earned from fitbit" might've lowered again; sometimes significantly, depending on when you last synced it.

Kimegatron

Make sure your Fitbit syncs up before 11:59PM for better accuracy. What is weird to me is that I will take the same walks every night, but my Fitbit always shows slightly different mileage on my walks.

ricer8

Thanks everyone. I do understand what everyone is saying, but it didn't used to be this way. For the last 2 years I've taken either a early morning walk or run and the calories burned were similar every day. I'm still following this pattern, but again the calories burned are all over the place. Just an oddity I suppose.