Accuracy of Fitbit?

rachmass1 · September 2012

Hi all, just trying to gauge the accuracy of my Fitbit in determining my TDEE and I looked at a one month history for my average and got 1,902 as average expendature per day, walking an average of about 5 miles a day (slowly, I have a treadmill desk set up).

Per Scooby and F2F my BMR is about 1,379 (current Scooby) and 1,385 (current F2F) and both would have me at lightly active I believe since my exercise is gentle walking and weight lifting, and a martial art once or twice a week (not high energy). Per Scooby, to lose weight at a 15% cut I should be at 1,612 per day, and F2F indicates 1,749. In the month long look at the FB it has my average calorie intake at 1,606 so I am at a deficit of just under 300 calories per day, which I thought would be perfect, but I am still at a plateau for two months now.

Is it possible that the FB isn't really that accurate for measuring TDEE even though it is pretty close to what Scooby and F2F indicate? I am very good at tracking what I eat and measure "most" but not everything.

I am absolutely NOT interested in eating too little as I want to make this a change for life, but from what I understand the plateau could be from either under eating or over eating and I am trying to figure this out and getting conflicting advice.

Much more leaning in the direction of the Road Map and EMTWL crowd than eating little crowd, but one thing that is really concerning me is my body fat is showing as increasing even with my weight being level, so I am doing something wrong still.

SW 180
CW 156
GW 130
Height 62 inches
Age 51
BF per Aria 39.5%

Been at this since @ 2nd week of January 2012

Throw out the FB as a method of measuring TDEE, eat less? eat more? Help please (sorry, I have posted before but this is really starting to bug me).

autumnk921 · September 2012

Have you checked out the Fitbit group on here? They may have the answers to some of these questions: (I would like to know that answers to this as well b/c I just started using my fitbit a little over a week ago & my fitbit calorie burn is way higher than what the calculators say for me)

http://www.myfitnesspal.com/groups/home/1290-fitbit-users

neurochamp · September 2012

Hi! I'm 32, but it looks like otherwise our stats are similar (I'm 5'4", 154lb). The TDEE and BMR levels, along with Fitbit numbers, you listed sound like they're pretty reasonable for your size & activity level.

My BMR is about 1410, and Fitbit calculates by average daily burn at about 2000/day over the last 30 days. I have my goals on MFP set to NET 1600/day, which usually puts me at about a 250-300 calorie deficit according to Fitbit (so, fairly similar to what you said, but I admit I walk a lot less than you do - I probably average 2 miles per day). At these settings I have been SLOWLY, but steadily, losing...the only major difference I can see based on what you described is that I do resistance/strength training (lifting weights per the New Rules of Lifting for Women book).

So my though/suggestion is that maybe you just need to change up your exercise routine a tad and add a little bit of strength training to your (excellent level of) walking? This has definitely helped me START to chip away at body fat % (I've gone from about 31% to about 30% in about a month - not a huge change, but I'm OK with that as long as it's moving downward).

The other thing that comes to mind - how are your carb/protein/fat ratios? Again, in my experience, limiting carbs to the 40-50% range and upping protein (I shoot for 30% but more realistically get to about 25% per day), and trying to keep sodium under 2500mg/day has been a big help.

rachmass1 · September 2012

Thanks guys, my diary is open and I am a bit carb heavy, but typically under 50%. I am a low sodium girl so sodium shouldn't be the problem, and I do lift pretty heavy (to failure at around 8 reps) at least 3 days a week. I should lift longer, but tend to just take 10 minutes here and there since I have a functional training machine in my office (my office looks like a gym).

My heart rate is really low, mostly around 50-55 at rest, and 70-80 while walking, so it never really gets up as high as it should. I have mixed in some elliptical workouts for 10-15 minutes a few times a week but lately I have run out of time (I am in school at the same time as running my own business, mom, and wife) so just want to base this off eating as opposed to exercising more, other than perhaps more weights added in.

What is the FB telling you guys for your activity score? Mine rarely gets over 700 so that might be part of the issue....

secretlobster · September 2012

I have a fitbit. I appreciate it for what it is - A cute, simple tool to help motivate people to move around more in their daily lives.

Unfortunately, "accurate" is exactly what a Fitbit isn't, especially if you are doing exercise other than walking. It's really a pedometer with a calculator function. Fitbit is a pretty good estimate of how many calories a person your age, height and weight would burn on average based on the number of steps you take, but if your heart rate runs low, your metabolism is likely to be higher than average.

If it's working for you, in terms of giving you a ballpark calorie estimate, then that's excellent. If not, maybe experiment a little bit. I use MFP's calorie estimate instead of FB's because I can change it manually, and I found FB to be recommending a lower calorie intake than I liked.

My activity score is usually around 400-600 on less active days, 800-1000 on active days (max was about 1200)

mgmlap · September 2012

looking at your diary..carbs are quite high..and protein doesnt seem high enough...

chicadejmu · September 2012

Sounds like you need to push yourself a little and get your heart rate up some. My fitbit activity level is almost always over 1000 because I try to make sure that I do elliptical or Jillian Michaels or some fast walks or something else to make sure I get at least my 10K steps in. Also, if I were you, I'd try eating more for a couple of weeks. If the scale goes up a little at first, don't freak out. But if after about 2 weeks you don't see it come back down, then maybe that's not your issue.

Of course, you could always get your Dr. involved.

And I do think protein helps - supposedly whey protein is thermagenic. Good luck! Hope things start moving in the right direction for you soon.

neurochamp · September 2012

I average around 800-900 activity score most days (it helps that I work from home a lot of days and am up and down stairs constantly). Occasionally (maybe one day per week) I'm over 1000. Like I said, I'm still losing, but very slowly

I did take a look at your diary, and it looks very reasonable (actually, it looks similar to mine - lots of Greek yogurt, pasta with veggies, salads, plenty of whole grains...). It looks like you're also getting close to 100g protein per day, which is excellent.

I would say ideally it would be great to extend the time you can spend lifting weights (shoot for at least 20-30 min 2-3x per week) and/or doing the elliptical workouts (again, 30 min at a time would be ideal, again 2-3x per week), but if you really don't have the time you could also try making a *slight* calorie cut (50-100cal per day) for about a month and see if that helps break your plateau? You want to make sure you're getting enough fuel so that you don't feel tired or burned out, so I wouldn't make a bigger cut than 100cal/day.

Have you ever looked into the EMTWL idea about doing a TDEE/metabolism reset? I've never done one, but if you've been at the calorie-cutting for a while maybe it's worth a shot? (If all else fails, anyway...)

Oh, and the Fitbit group on here is pretty good, so I second checking that out.

secretlobster · September 2012

Oh, I forgot to mention - Your "activity score" changes based on the amount of activity you've done in the past. So it gets harder to get, or maintain, a higher "score" as fitbit deems you to be more fit.

rachmass1 · September 2012

looking at your diary..carbs are quite high..and protein doesnt seem high enough...

I don't quite understand this as they are under the percentage set by MFP for carbs and usually over on protein. Are you talking about the Macros that are discussed on EM2WL? I don't really understand those or even how to change them on the profile.

Thanks!!!

neurochamp · September 2012

From "My Home" click "Goals," then "Change Goals." Check "Custom" then "Continue" and you'll be able to set your macro ratios to whatever you want.

I think the EM2WL group and many people who lift recommend 40/30/30 (carbs/protein/fat), and that's what I have my goals set to. The default setting in MFP has your protein goal ridiculously low (but, based on your diary, you usually go over - that's a good thing); not getting enough protein MIGHT make it hard to maintain muscle while you lose weight/body fat. For me, eating extra protein helps me stay full longer. At the very least you might want to consider increasing your protein goal to the 25-30% range.

rachmass1 · September 2012

From "My Home" click "Goals," then "Change Goals." Check "Custom" then "Continue" and you'll be able to set your macro ratios to whatever you want.

I think the EM2WL group and many people who lift recommend 40/30/30 (carbs/protein/fat), and that's what I have my goals set to. The default setting in MFP has your protein goal ridiculously low (but, based on your diary, you usually go over - that's a good thing); not getting enough protein MIGHT make it hard to maintain muscle while you lose weight/body fat. For me, eating extra protein helps me stay full longer. At the very least you might want to consider increasing your protein goal to the 25-30% range.

Thanks, I didn't know how to do that. So simple. Thanks again!!!

Graelwyn75 · September 2012

I honestly have no idea, but when I was eating close to the total I got from the fitbit and my hrm, with my setting at sedentary, I was maintaining my weight, which was my intention, and sometimes that was as high as 2800-3000 calories, with my cycling. Today it took me up to 2200 calorie goal just from doing some walking, but I generally get between 10,000 and 22000 steps per day.

Accuracy of Fitbit?

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