Confused on calorie burn process ..

[Jeroniymo]

Hi

I was wondering if anyone can explain to me the way that the fitbit app works with calorie burning stats.

I understand that the BMR is taken using stats and this is used to work out a resting calorie burn every ...

It is the exercise burning calories that confuses me.

i have been monitoring steps, distance, active mins etc. 

Today I noticed I had done more steps distance and active minutes than most other days, yet when I add on my remaining BMR calories to my current burn, I would have burnt less calories than previous days.

please note I have a flex so no heart rate monitor to fine tune calories burnt.  My problem is I wNt to ensure I hit my calories burnt target of 3200.  My BMR is close on 2000, so I need to ensure I burn 1200 in exercise each day, not sure how I can ensure I do this the way the set up is done.

cheers

[A_Lurker · Accepted solution]

I don't know how the non-HR versions work, but I would assume that how quickly you take those steps could affect the overall calories burned. I went back to a point where I was using the one.  592 steps in a 15-min period was marked as moderate, but the 150 steps in the next 15-min period was marked as light.  The calories burned were 93 vs 40.

592 / 93 =  6.4 steps burned 1 calorie

150 / 40 = 3.75 steps burned 1 calorie

So it's possible that you have done more steps at a slower pace.  I'm not sure if it's right, but I've seen it said that active minutes only start counting after 10 in a row.  That could easily end up skewed depending on your daily movements add up.

[Jeroniymo]

That makes a lot of sense and it would explain the difference.

I suspect that on the day with less steps I did a couple of hills and this would have made me take aome steps quicker - i tend to push harder going up a hill and down hill I obviously take quicker steps.

todays walk was along a flat river - so my pace was very constant.

cheers

[A_Lurker]

No problems, although I don't think my numbers make sense.  They are almost counter-intuitive.  I broke a day with all three (using 5 mins).  Calories are adjusted -8 calories as that is what it said I burned at 0 steps.  Interesting as it appears that without factoring in HR you might get a higher report if they are more even through the day.

	Steps	Calories	Steps/cal
Light	11	3	3.67
Intense	365	68	5.37
Intense	464	79	5.87
Intense	429	82	5.23
Intense	385	82	4.70
Moderate	100	27	3.70

[Jeroniymo]

I thought I had this, and was eating so I had 1500 calorie deficit, but have just noticed that as the day goes on after my last meal my deficit decreases rather than increases ( as it should do due to BMR) why is this?  it makes planning calories really challenging!

Can anyone wxplain to me why in the last half hour I have a net gain of 8 calories when I have eaten nothing?

[A_Lurker]

The system estimates what you're going to burn for the rest of the day.  Depending on how consistent you are will depend how accurate it is.  In my case I tend to go to sleep most nights before work by 10pm.  It still assumes I'll burn some calories.  I usually take a snack around 9pm and I'll take a look at the actual vs eaten and decide what I'm going to eat.  At this point I'll guess and I'll either hit dead on where I want to be or maybe end up 100-200 calories lower.  It's too early in the day to guess, but here's where I am now:

I'm set to a 1000 calorie deficit at the moment.  So, my ChargeHR is assuming I'm going to burn 2918 calories by the end of the day.  This will change if I'm more or less active.  Since I prefer to have a decent snack before bed I'll keep my dinner around 600-800 calories (haven't quite decided the side dishes yet, but went out and bought new potatoes, green bean, and garlic - well, bought way more). Here's where I actually am:

This is the one I check closer to bed time.  If you're less active in the evenings then just keep an eye on this one before dinner.  Don't forget that you've still got hours to burn.  If I do nothing else the rest of the day (not make dinner, not do laundry, not swim, not water the plants) I'll burn an extra 600 calories, bringing me to only 2500 calories instead of 2900 calories.  The longer you look at the numbers the easier it becomes.  I think you can also change the setting to sedentary.  That way you need to burn more of your calories before the system says you can eat them.  It assumes I believe at all times that you are going to do nothing more for the rest of the day.

I changed my settings to sedentary, and I get:

See, I'd already guessed that it would be 2500 calories if I did nothing until the end of the day.  I'm pretty good at guessing later in the day.  If you're not you can change yours to this setting.  In the morning though your calorie count will be very low.

[Dominique]

If you are purposedly active 1 hour per day, that still leaves 23 hours during which you will burn quite a lot through NEAT (non-exercise activity thermogenesis). Your Fitbit should figure it out pretty well, even if it hasn’t got HR monitoring capabilities. Fitbit as a company has been around for some time already, they know a few things about tracking activity and have fine-tuned their algorithm accordingly. That’s why I wouldn’t spend too much time questioning the validity of the calories burned as reported every day. Since your goal is to lose weight and you are logging your intake, use that to assess whether calories out are correct or not. 

[Jeroniymo]

thank you for the detail... in my mind having the setting to sedentary is the option i want, but cannot work out how/ where to change it - could you fill me in on this please?

thanks

?martin

[Dominique]

Have a look at Fitbit’s Food Plan Demystified. Explanations about Personalized vs. Sedentary can be found in part 3.