Calorie allotment suddenly changed...

[amac23]

Hi All!

This is day three of my fitbit and I am loving it!

I do have one question- does the calorie allowance change daily based on what you do? I am used to a set amount and for my first two days I as given about 1200 a day (on a 'medium' plan). Today it's at 2000. Today I am much more active than I was this weekend- so I am just wondering if it automatically adjusts each day.

Thanks!

[SunsetRunner]

Yes the callorie allotment can fluctuate upwards if you are more active than the info you inputted when you set up the Fitbit.  The goal is to keep your calorie deficit constant (or as close to the same everyday).  For example if my BMR is 2,500 calories and I have a weight loss goal of 1lb/week (3,500/7 = 500 calorie deficit/day) then Fitbit will say I can eat 2,000 calories.  Now the next day I run a 5k and burn an extra 1,000 calories (on top of what Fitbit expected) then I would be able to eat 3,000 calories (2,500 + 1000 - 500).  Hope that makes sense for you.

[amac23]

Thank you 🙂 That does help, yes- I am not used to seeing the flexibility- so nice!

My only concern is this: the main workout class I take at my gym is a dumbell class- medium intensity toning. I don't bother logging any workouts because I am assuming that my flex is picking up on heartrate/ activity- etc. However- I keep seeing people post about logging their workouts- isn't that supposed to be taken care of? I took an hour long class tonight and noticed that my dashboars says I've had zero active minuted.

[gerrymcd]

Fitbit only logs steps - it doesn't take account of you heart rate, how much weight you lifted, etc.  I wear a bluetooth heartrate monitor connected to my iphone.  This uploads my workout minutes, calories burned, etc directly to my fitbit dashboard.  Heart rate monitors are well worth the cost, especially since they are now really comfortable to wear.

[tmhaines]

I have a Polar HRM and would love for it to upload to FitBit as well as the Polar Trainer.  What HRM do you use that synchs up with FitBit?

[MrPete]

Yes, calories burned calculated by fitbit vary depending on your level of activity.  Fitbit does not measure your heart rate so can't really tell how hard you are working but it can measure acceleration and rate of your steps as well as number of steps so that it can estimate your activity level.  Fitbit makes assumptions and estimates how your activity is going to be for the day.  The more you use it the more accurate its estimations become. 

There is also a setting that you can make to have fitbit subtract calories, so if you are having a couch potato day it will reduce you calories that you can consume.  It will also reduce the number of calories of certain excercises, for example I do a fatburn level on my treadmill every morning while wearing my heart rate monitor.  The monitor says I burn 400 calories, fitbit will usually subtract about 150 from that.

I link my fitbit to myfitnesspal which shows me exactly the adjustment that fitbit is making.  My heartrate monitor links to fitbit via an iphone app called digifit. 

[slysam]

Mr Pate, The Fitbit Adjustment you refer to is specific to Myfitnesspal users who have their fitbit and MFP accounts linked. MFP actually calculates the fitbit adjustment by comparing your total fitbit calorie burn to what MFP expects you to have burned according to your MFP activity level. Fitbit doesn't take calories away if you log an activity, it replaces whatever the fitbit had estimated with what you log. This can cause your total to go up, do down or stay the same depending how what you logged compares to what the fitbit had estimated. The fitbit adjustment you see on MFP does not correlate with any number on fitbit, it should simply end up being the difference between what MFP estimates someone with your stats would burn in a day plus any exercise you log on MFP. If you are logging exercise on MFP, that is actually excluded from your fitbit adjustment on the MFP site.

[slysam]

Yes to what everyone said about the allowance varying by your actual activity. And also agree that you may want to log you workout if it is weight training or a non any type of resistance training.

[SGreen09]

Do I have to use the extra calories allotted each day due to my increased activity?  What happens if I don't?  And, I have the Fitbit HR - does that track my workouts so that I don't have to log separately as an activity?

[slysam]

---

@SGreen09 wrote:

Do I have to use the extra calories allotted each day due to my increased activity?  What happens if I don't?  And, I have the Fitbit HR - does that track my workouts so that I don't have to log separately as an activity?

---

I haven't noticed how well the HR fitbit's do with strength training so I will leave that to someone else. Usually HRM's are better at estimating aerobic activity and strength training is anaerobic. But about the other... If you chronically undereat and take in inadequate nutrition it can slow your metabolism so you burn at a slower rate than you should. This is where the controversial "starvation mode" comes in. "Starvation mode" doesn't stop you from starving, but it tries so it slows the metabolism. Obviously you would still waste away if you continue to undereat. It can be a problem if you undereat for long enough that it kicks in then you go off your diet and eat normally. Some people find when they go off a very low calorie diet they regain weight quickly and end up gaining a little extra. This can lead to the yo-yo dieting pattern where you lose weight by depriving yourself, feel horrible, go off the diet than regain the weight plus a little extra. Getting a little fatter each time. If this sounds familiar to your experience, you might want to re-examine your pattern. I don't think it is a big deal to be under once in a while though. Some people even fast periodically for diet or religious reasons with no issue. The allowance is just subtracting your weight loss goal from what the fitbit estimates you burn. So if you say you want to lose 1/2 pound a week, it subtracts 250 calories from your burn for the day. The Fitbit is estimating your burn and in this case -250 isn't underating by much anyway. If someone on this plan ate -500 they might still be fine--it depends on their actual burn (as oppose to the estimate), how long they have been undereating, how good their nutrition is, how much body fat they are already carrying, and maybe lots of other variables. So it is hard to say one size fits all with diet. But undereating on a -250 plan probably isn't an issue unless already very lean. But undereating on a -1000 plan is more likely to be an issue again depending on various variables.