Help! I don't trust my Fitbit.

I enter my work outs on the fitbit app. It will increase your burn there and rollover to MFP. I found fitbit estimates to be more accurate. As much as I would love to believe I burn over 400 cals doing Insanity Max30 like MFP says I believe the 200-280 I get on fitbit is more realistic.

On here I'm set to sedentary with negative adjustments. I only log food on MFP and only log activity into fitbit. It works for me.

Anecdotally regarding Fitbit....After doing TDEE calcs over 7 different sites (yes I'm a geek that way - I like data), the moderate TDEE and Active TDEE estimates for me were roughly between 3100 (moderate) and 3400 (Active). BMR's are around 1900, which is where MFP starts with me.

Fitbit is telling me that I hit between those numbers pretty much every day. I'm a 54 yo male, 5'11" and about 226, down about 14 lbs so far, but only tracking Fitbit calories closely for a couple of weeks (when I started I was all over the place before settling on my tracking method). I've been generally eating about 1950 a day and intending to bump that up a little so as not to under-eat.

Anyway, the point of the post is say that Fitbit seems to say that my TDEE is about what the estimates are, i.e. fairly close. Over time we'll see how close it is. I don't have enough personal weight loss data yet to make a claim on it, but I think I trust it more than when I started.

CSARdiver wrote: »

I've never been a fan of the wrist HRMs for this reason. These are inaccurate (compared to the chest models) and you are better off with manual estimations. HRMs are designed for long sustained steady state cardio - all calorie estimations are based on this base data.

In short - running, biking, swimming - HRMs good. HIIT - HRMs bad.

Define "manual estimations". There are exactly zero online calculators that have an option that remotely resembles my life (on my feet a ton; typically getting 15,000-20,000 steps/day; chasing and carrying young children; but *not* doing large amounts of high intensity cardio). They all assume that as you start spending more hours doing physical activity, that physical activity gets more intense. That's the main reason I use a FitBit. My actual weight loss results showed me that my best guess based on the online calculators was miles off for me. Conveniently, the FitBit numbers match my actual weight loss results.

I think you misunderstand what negative adjustments are.

If synced, MFP compares what it expects you to burn (total, all day) to what Fitbit says you burned (total, all day). If your actual is less than MFP expected, this is where negative adjustments matter.

Lets say you are supposed to burn 2000 and you have a 500 calorie deficit, so MFP tells you 'eat 1500'. But you have a lazy day and Fitbit says you only burned 1800. If you do not have negatives enabled, your Fitbit adjustment is 0 because its not allowed to go negative. MFP still tells you to eat 1500, and you have a smaller deficit but if you're not paying attention you may not realize it. If you have negatives enabled, your Fitbit adjustment is -200 and MFP tells you to eat 1300. Deficit intact.

Negative adjustments only matter if your actual burn is lower than projected. And MFP still will not go below 1200 on its recommendation of what to eat.

Christine_72 wrote: »

@StaciMarie1974 thank you. I was always under the impression that you wouldn't get negative adjustments if you disabled the feature here on mfp, Obviously i was wrong.

I know all about the projected activity level, I am set at sedentary. I pretty much stop moving after dinner at around 6pm and go to bed around 8. So that's 6 hours at or around BMR levels

PokeyBug wrote: »

I didn't trust my FitBit, either. It was wildly inaccurate as far as measuring calories I burned, always way too low for the activity I'd performed while wearing it. Fortunately for me, mine was a gift, so I didn't lose any money.

Ditch the Fitbit, find a fitness calculator that seems reliable, and use an accurate calorie needs calculator. I use one based on the Mifflin-St.Jeor formula, which I've found is pretty accurate. (I wish I could connect you with one online, but the one I'm using was given to me by a friend. It uses M-SJ and multiplies my BMR by an activity factor of 1.6 for slow/sedentary job.)

Looks like the problem wasn't your FitBit - but that you are on the higher end of the normal distribution for metabolism. An average person would only multiply their BMR by 1.2 for a sedentary lifestyle. If multiplying by 1.6 is right for you, you're burning quite a few more calories than the average person - which is why your FitBit was underestimating (because it uses formulas for the average person).

The other possible explanation is that you're overestimating the calories you consume.

None of which really matters because you've found the right match between calorie intake and burn - but I mention it because it's not common for people to find that their FitBit seriously underestimates their burn.

1st- Fitbit sucks. Take it back. They will take it back for up to three months. So just return it. It can't judge your type of workout properly, so why even have it? Buy a cheap pedometer if you want to see how many steps you take and a HRM if you want to know how many calories you are burning. Seriously, I had a fitbit, and if I had exercised every minute I spent trying to get the thing to work right with MFP I'd already be skinny.

2nd- For HIIT and yoga it's hard for anything to give you an accurate idea of your calorie burn. Just decide on a number for those sessions and log that. If you are doing yoga and HIIT you aren't sedentary. Maybe don't log the exercise and just change your activity level if you don't feel comfortable just setting something up. Whatever works for you.