Fitbit accuracy/calorie counting

Hi friends! I have a fitbit versa. It scans my heart rate, steps, calories and all that good stuff. The past couple days it was saying I burned about 4000 calories in one day. That's from my exercise, job and just regular daily calories you burn. Mfp has me at 2000 calories I should eat a day. This means I would be eating half the calories I burn. Since 3500 calories are in a pound, at that rate I would be dropping weight quickly. That's like 4lbs a week. But I'm not losing that. Lol. Am I calculating wrong here?

Replies

  • yirara
    yirara Posts: 7,352 Member
    edited March 17
    Any device only estimates. if for some reason your heartrate might be elevated without you doing anything then some devices see that as you being active and give you crazy burns which aren't there. Another option is that you're moving an awful lot.

    Can you tell us a bit more on what you do that the moment? You can also look at the fitbit website to see where those high burns come from (unless that info vanished behind a paywall of course). Is this active calories or base calories? Are you a bit sick at the moment? Or using an asthma inhaler or other medications that increase your heartrate? Did you set custom heartrate zones?
  • Ladyamanda87
    Ladyamanda87 Posts: 36 Member
    I run a inhome daycare so I am moving alot! It does tell me when I'm in fat burn zone when I'm exercising. Because I am 360 my heart rate does go up alot. Not sick and the only medication I have is birth control and synthroid. I did not set up any custom zones
  • yirara
    yirara Posts: 7,352 Member
    How many steps do you get in a day? With a weight of 360lbs you could easily get more calories, even with a weight-loss target of 2lbs/week you might be undereating a lot with just 2000 calories/day. What activity level did you chose when you set up MFP? I've just chosen a random size and age (170cm, 35 years) and your weight, and a higher activity level, and I got a TDEE of 3600 calories/day. Take 100 calories for 2lbs per week off and you'd get 2600 calories. Why not play with the activity levels. If you get 10k steps per day then you're certain active, maybe even very active.
  • Ladyamanda87
    Ladyamanda87 Posts: 36 Member
    Hmmm maybe that's the issue. I think I have it set to sedentary. My steps vary.
    Monday- 11,000
    Tue-9560
    Wed-13,200
    Thu- 7,800
    Is it possible I'm not eating enough and my body is holding onto the weight? I haven't lost anything in a month. Idk if that's a myth or not lol. Thank you so much for all your replies!
  • yirara
    yirara Posts: 7,352 Member
    Ok, with these steps you're certainly active I'd say. But no, your body is not holding onto fat if you eat too little. Think of starving people in third world countries: do they look fat? No, they get thinner and thinner, and eventually die.

    How do you measure your food intake, btw? Do you use a scale and measure everything, or are you estimating, using spoons and cups, or any other method? Maybe you could open your diary so people might spot some logging errors and help you.
  • Walkywalkerson
    Walkywalkerson Posts: 447 Member
    I think Fitbit over estimates calorie burn by a lot.
    Most activity trackers do.
    I did a 2hr walk yesterday and my Fitbit recons I burned 800 calories!
    I highly doubt that lol
    I put the walk into MFP and it estimated 500 calories which I still think is pretty high.
    I don't take any of it literally and usually halve the estimated calories.
  • AnnPT77
    AnnPT77 Posts: 24,812 Member

    OP, in addition to Yirara's good questions, how long have you been at this, tracking calories and your body weight? How long have you had the Fitbit (and worn it consistently)?

    I see that you say you haven't lost weight in a month. Have you been tracking longer, and were you losing previously? If so, how fast? Or is this the first month? (Some women only see a new low weight once a month, at a certain point in their monthly cycle, because hormonal water weight shifts can be that weird. That's not the common case, but it's possible. Birth control meds wouldn't necessarily prevent that.)

    Some good brand/model trackers "learn" their user over time, and adjust their calculations based on data they've collected. That can take a couple of weeks. They still can be inaccurate, high or low, but probably will tend to be consistent in the direction/magnitude of inaccuracy (in the all-day calorie burn numbers), potentially still be helpful once you know that.

    Yirara is giving you good guidance, asking the right questions. She's correct about the "holding on to fat because too few calories" idea. That doesn't happen with true starvation.

    Eating too little can lead to fatigue (maybe subtle), so sometimes can make a person lose fat more slowly than they'd expect on an ultra-low calories. This can happen because fatigue makes us move less, and even fidgeting less can be in the low hundreds of calories daily, let alone sleeping/resting more or being less energetic about daily life stuff or in exercise sessions. Also, at ultra-low calories, the body may slow down hair growth - cause hair loss that way, a few weeks down the road - or may turn down body temperature slightly, and that sort of thing. It won't stop weight loss, just make it slower than expected.

    In addition, too-low calories is a physical stress on the body, can increase stress-related water retention, gradually, by multiple pounds. That doesn't stop fat loss, but it can hide fat loss on the scale for a while. (That tends to sort itself out, with time, as long as the situation isn't extremely extreme.)

    Undereating is a bad plan, counterproductive, increases health risks. Fat loss won't stop, though.
    I think Fitbit over estimates calorie burn by a lot.
    Most activity trackers do.
    I did a 2hr walk yesterday and my Fitbit recons I burned 800 calories!
    I highly doubt that lol
    I put the walk into MFP and it estimated 500 calories which I still think is pretty high.
    I don't take any of it literally and usually halve the estimated calories.

    Vast overgeneralization. Fitness trackers may overestimate some types of exercise (or underestimate them), overestimate for some people (or underestimate for others), etc. Some of those discrepancies can even be predicted. Thinking that the numbers trackers estimate are gospel truth is a bad plan, though - that's true.

    Looking at an individual exercise estimate, the device may be off, but all-day estimates may still end up close, loosely via something kind of analogous to the law of large numbers . . . or in this case, maybe semi-large numbers. Over on some things, under on others, total comes close.

    Any given individual, when calorie-counting carefully, can compare their weight changes in context of calorie intake to what their tracker says, make pretty intelligent inferences about whether and how to adjust the tracker's estimates to be useful for them, possibly (after giving the tracker a couple of weeks to "learn" them, in a statistical sense).

    Even when the tracker is off for an individual, it's as much - maybe more - about the person being non-average, vs. the tracker simply being wrong.
  • sijomial
    sijomial Posts: 19,620 Member
    edited March 18
    "Mfp has me at 2000 calories I should eat a day."

    It only set that goal (for a day with no exercise remember) because you picked sedentary when you are a million miles and a lot of steps away from being mostly seated which is what sedentary means.
    "I run a inhome daycare so I am moving alot!" - which is the opposite of sedentary!!

    Putting in wrong data gives an incorrect calculation. Suggest you redo your goal setup to get a more realistic estimate for someone both heavy and moving a lot.

    Although a synced Fitbit will try and adjust that up to your true very active level it means the MFP goal is badly wrong and you will be getting massive adjustments due to both your activity and exercise.
  • PAV8888
    PAV8888 Posts: 10,695 Member
    You're starting at a spot where joining MFP and taking care of your health makes a great deal of sense! And it means that you need to CONSISTENTLY and SUSTAINABLY and for a considerable amount of time take in a good amount of calories less than you spend.

    But, as many people discover sooner rather than later, you cannot consistently and sustainably achieve this if you OVER-DO things. And doing things sustainably starts from setting sustainable goals.

    You are not sedentary. And even though there is an extremely high likelihood that your high heart rate is showing up on Fitbit as calories spent.. which you didn't spent, there is also an extremely more high likelihood that the amount of intake that you log is under-estimated: not because of your intentions but because of how easy it is to make mistakes even when people have no intention to.

    So you can just lift your hands in the air and say all this can't work. OR you can lift your hands in the air and hope that the errors balance each other with no effort on your part. Or you can concentrate on achieving consistency by trying to minimize all errors! :wink: I bet you know which one I believe works best in terms of providing you with actionable information.

    Grab yourself a weight trend application. Consistently weight yourself under similar conditions and track your progress there. Adjust your goals reasonably based on your as accurate as possible logging. Review your logs. Make decisions as to which things work better or less well for you over time (these DO and WILL change as you progress). Log the good, the bad, and the ugly. Show up every day... and slowly make changes that you see yourself being able to continue with for the indefinitely long term.

    And drop by the larger losers group. There is some really good info in many of the early posts by Novus... https://community.myfitnesspal.com/en/group/133315-larger-losers
  • yirara
    yirara Posts: 7,352 Member
    Yay, so glad more people showed up here. Thanks guys.
  • Ladyamanda87
    Ladyamanda87 Posts: 36 Member
    Thank you everyone! This is the most support I've honestly ever had ❤ it's a struggle but I've lost 30lbs so far actually since July. I always feel like it should be more, and I haven't lost anything since end of January now. I did recently buy a food scale to weigh everything out! So hopefully that helps. I do have a hard time drinking alot of water. I'm just not a thirsty person, but I'm trying to do better. Thank you to everyone who had something to add! I gotta get more fit so I can be around for my kiddos
  • AnnPT77
    AnnPT77 Posts: 24,812 Member
    Thank you everyone! This is the most support I've honestly ever had ❤ it's a struggle but I've lost 30lbs so far actually since July. I always feel like it should be more, and I haven't lost anything since end of January now. I did recently buy a food scale to weigh everything out! So hopefully that helps. I do have a hard time drinking alot of water. I'm just not a thirsty person, but I'm trying to do better. Thank you to everyone who had something to add! I gotta get more fit so I can be around for my kiddos

    This is a rough approximation, not a sure thing, but:

    If your weight loss slowly decreased over a period of time, with no major changes in eating or activities/exercise, and you haven't had any health issues (infections or viruses or injuries), then it may be that you gradually reached maintenance calories for your current weight. Since we're thinking that your current maintenance would be more than the number of calories you're logging, tightening up logging as you're planning to do, and questioning exercise calories (including your Fitbit's estimates) if you're eating those back, would be good things to look at. I think you're on a good track with those ideas.

    However, if you were previously losing at a good clip, then stopped suddenly around the end of January, I'd be more inclined to suspect some kind of water retention effect as a least part of the situation. There can be diverse reasons for that, including simply sticking with low calories for a long time, other forms of stress, etc.

    This is a good article about that:

    https://physiqonomics.com/the-weird-and-highly-annoying-world-of-scale-weight-and-fluctuations

    The article's focused on short-term water retention, but goes through some of the triggers. Same triggers can cause more persistent water weight increase, for some people, depending on the situation.

    I'd second the recommendation of the "Larger Losers" group PAV recommended: Nice people, good support there. It's for people who have or had 75 pounds to lose, and includes folks at various stages in the process.

    Best wishes!
  • nooshi713
    nooshi713 Posts: 4,839 Member
    I have a Zip, which is a step counter. I feel it is very accurate. I have used heart rate monitors before and they overestimate my burn a lot because my heart rate goes up a lot during exercise.