Calories burned on a day

[Floris0023]

Hi,

I bought my fitbit charge 3 this week. But i have some questions regarding the calories burned on a day.

on this foto (https://imgur.com/qxLOD4W) you can see that I already burned 2952 today. I had a 5km run and burned 368 during this exercise. That means that over the rest of the day i burned 2952-368 = 2583 calories. Now my bmr is around 2016 calories a day. So at this time I burned 1638 just to let my body work. So 2583-1638 = 945 left.. So where does these calories come from. Just the steps i took during the day? Seems a bit odd that 9576 burns 945. Just wanna understand how these calculations work. I wanna lose some fat so its important that the calories i burn in a day are somewhat precise. Hope somebody can help me and explain it to me 🙂

Thanks in advance!!

[RiseAndShine]

@Floris0023, welcome to the community. Did you account for calories burned during the night? Every morning I see at least over 400 burned just as I sleep... simply because our bodies still have to function and, thus, burn calories.

You can get more information about the way how Fitbit estimates calories burned here.

Best of luck!

[Floris0023]

that "simply because our bodies still have to function and, thus, burn calories." is also known as you BMR. So yes i accounted that for sure as you can see in my post. But thanks for the help 😉

[Dominique]

A more relevant graph (if you want to know how your energy expenditure was spread during the day) would be this one:

It displays calories burned throughout the day in slices of 5 minutes. The baseline (BMR) would typically be during your sleep. Everything else taller would be some kind of activity, even if it’s only standing in the kitchen preparing food, socializing with friends etc. A large portion of your energy expenditure is NEAT (non-exercise activity thermogenesis).

PS: note that the Fitbit forum platform willl let you insert inline pictures (just click on the "Photos" icon in the toolbar when preparing your post). It’s more convenient for community members reading your post to see included pictures right away, rather than having to click on a link and open the picture on a third-party site.

[Floris0023]

Yeah, I am aware that when I am moving throughout the day I will burn more calories. I just wanna know how accurate these heart rate measurements are. 3,558 calories burned seems quite high. I only run 5km responsible for 368 calories burned and my BMR for 2,016 calories. There are 3,558-2,384=1,174 calories left. Are those calories just from my higher heart rate and movement throughout that specific day? The higher your bpm the more calories you burn right?

Also thanks for the tip! From now on I will provide the photo's directly in the post and not trough third-party sites.

[Dominique · Accepted solution]

It’s important to realize all of this are estimates, with a margin of error. There are more accurate ways of measuring energy expenditure during effort, but there’s a trade-off between accuracy and convenience: for instance, you may have to run on a treadmill with a mask on your head, instead of simply wearing your Fitbit while running outdoors.

Yes, HR (if supported by your Fitbit) is one of the factors that affect the way Fitbit estimates your activity, but it has other means to do it, for instance via its accelerometers, which also detect your movements and their intensity, impacts etc.

People are usually concerned by the accuracy of calories burned if/when they plan to use it for weight management, when also logging in their intake. If this is your case, you can assess the accuracy by weighing yourself on a regular basis and comparing the predicted change in weight to the actual change reported by the scale. After a few weeks/months, you should have a pretty good idea. If course, there’s also a margin of error with calories in: you may forget to log some items, food labels have incorrect info etc.  

[Floris0023]

Thank you for all the support Dominique, really appreciate it. I am aware of the fact that the Fitbit is not 100% accurate and that is fine. You cant expect that a fitness tracker is getting there with the exact measurement any time soon. I am very happy with my fitbit so far. The activities such as running and cycling are very accurate with all the stats.

I know for a fact that my calories in are 100% precise. I log and weigh everything I consume, so that is not a problem I will encounter. I will see what the scale is gonna say the upcoming weeks with the current calorie deficit I am in right now. We will see how precise this device actually is, hope to see great results on the scale 😉.

Thanks for all the help,it is much appreciated.

[emili]

@Floris0023. hey there, if you feel that @Dominique has answered your question, please consider marking his reply as a solution so others can benefit from his advice. if you still have question, lay em on us... 

[Floris0023]

@emili It does not answer it quite yet, but it is helpful though. My question will be answered over time. For now I will just wait and see what the scale is going to say. That will be my definite answer.

[JimC_99]

I have been tracking my calories in/out and my weight for about 46 weeks now, and I find that my Charge 2 is ~ 39% High in the calories burned.  I have also tracked my weight loss using the NIH Body Planner web site with a light activity multiplier and it is ~ 3% off (high) My metabolism and weight loss seems to follow the NIH site more closely than the Charge 2.  I have also adjusted the heart range numbers in my profile up, so the calories burned are lower and I also state that I am wearing the tracker on my dominant hand (I'm not) to try to reduce the calories out.

[Floris0023]

Hi @JimC_99,

Thank you for your response! I don't know if there is any difference in hardware between the charge 2 and 3. How have you found out that your Charge 2 is overestimating the calories by ~ 39%? I am in a 1000 calorie deficit according to my Fitbit each day. I have done a lot of calculations and research to find out how precise the Fitbit actually is. I have come to the conclusion that if the heart rate measurements are almost exactly the same as your actual heart rate. The Fitbit should be right with the calories I burn everyday. I will be logging my weight each week to see if the Fitbit is actually right. I should lose around 2 pounds (0.9 kg) each week with a calorie deficit of 1000. I will keeping your tips in mind, if I don't lose as much weight as my Fitbit says I should. I will update this post when I know more! 🙂

[JimC_99]

I log my food using the fitbit app and use Excel to track bmr calories burned and calories consumed.  I track my weight with a scale that imports into Fitbit and I also track in excel.  Based on the Charge2 burned calories,  calories in and actual weight my calories per pound loss is around 4400 and the fitbit probably  uses the standard 3500.  Based on the fitbit, I should be down about 130 pounds but I am actually down around 95 pounds.

[JimC_99]

One thing that I have done recently was to break out the data I have into 4 week increments and  have noticed that as I lose weight, the Fitbit calories burn appears to be more accurate.  After about 8 weeks, the data becomes more stable and most of the error occurs in the early part of the weight loss cycle.  I plan on tracking until I get to my goal weight so I will still get a lot more data..😊

[Floris0023]

First of all congrats on your progress! Sounds good. I use my fitnespal and a scale to log all my food in, I connected the Fitbitapp with mfp so my calories consumed is displayed on the Fitbit app. I hope to see great results the upcoming weeks, hopefully already lost a pound next week. But we will see how accurate the Fitbit actually is over time. I am very curious 🙂

[Dominique]

---

@JimC_99 wrote:

I have been tracking my calories in/out and my weight for about 46 weeks now, and I find that my Charge 2 is ~ 39% High in the calories burned.  I have also tracked my weight loss using the NIH Body Planner web site with a light activity multiplier and it is ~ 3% off (high) My metabolism and weight loss seems to follow the NIH site more closely than the Charge 2.

---

Impressive weight loss (looking at your TrendWeight), @JimC_99! Clearly shows a lot of dedication and consistency!

Regarding metabolism: Fitbit doesn’t make any attempt to factor in any reduction in metabolism that results from a major drop in body weight. For all it "knows", your metabolism is that of a guy your age / your (current) size who has maintained that weight (your current weight) for a while. Does the NIH calculator take into account the reduction in metabolism?

Since the "light" activity level appears to match your numbers, what’s your average step count in Fitbit?

[JimC_99]

@Dominique  - thanks!

I don't think the NIH planner adjusts for metabolic changes but I don't know the underlying algorithms used. 

I usually average around 5K steps per day and go to gym 2 to 3 times a week.  I do about 40 min of resistance training using Cybex machines ( haven't lifted free weights for 40 years, so not ready for those yet..🙄) and about 20 min of cardio.  To be honest, I could work out harder, but I am trying strengthen my core and back first.  I have had back issues in the past from a sports injury,  so I don't press real hard.....

[Floris0023]

If i may ask @JimC_99. On what calorie deficit are you right know and how many calories do you eat in a day? Very curious to know, because to me and don't take this in the wrong way 5k steps a day and 2 to 3 gym times a week ins't that much. I find it inspiring how you lose so much with the activities you do weekly.

[JimC_99]

My target deficit is 750 calories per day, to lose 1.5 lbs per day.  I have actually been around 2100 calories per day average, which is close to my BMR.  I have been losing 0.8 to 1.3 lbs per week (for the last 4 to 6 weeks), so I assume that since I tend to eat the same amount, I will reach a steady state equilibrium.  I would like to actually increase my intake to stabilize for a while, to see if my metabolic activity will increase.

[JimC_99]

Spoiler

When I started this journey, I was 6'3" and 370 lbs, so I was carrying a 150lb person around constantly.   Now it is down to a child size, but is still there...🙄🙄

 Not sure why it is a spoiler...?

[Dominique]

@JimC_99 is right: when you weigh 300+ lbs, life is a workout.