I have a question about Fitbit and TDEE

[2017Resolutions]

I used myfitnesspal and multiple TDEE calculators. I plugged in my stats, clicked sedentary, and most of them said my TDEE was 1800. So, I presumed this meant if I ate 1800, I would maintain my weight. I then went about eating 1300. I haven't lost a pound. I also haven't gained a pound. 

I bought a fitbit to keep myself motivated and noticed that my actual calories burned was hovering around 1200. Does this mean that my TDEE is actually 1200, not 1800? And if so, how am I supposed to lose weight? If I ate at 500 defecit to lose 1 lb a week, I'd die. I am trying to be more active, but I work 12 hours a day and need to remain seated. 

[GershonSurge]

Most likely, you are eating more than 1,300 calories a day. Are you weighing or otherwise measuring all your food?

Rather than using a TDEE calculator, I suggest using a Basal Metabolic Rate (BMR) or Resting Metabolic Rate (RMR) calculator. It's not considered healthy to ingest fewer than this number of calories.

In any case, it would be difficult to maintain your health with a job that requires sitting 12 hours a day.

[2017Resolutions]

Hi! I'm not sure I understand your response. My basic question is whether or not the calories burned shown on the fitbit app is meant to be my TDEE (or, rather, is that the entirety of what my body burns?). If so, I'll have to eat less.

As for measurements of food, I own a food scale and measure everthing in grams (excepting liquids for obvious reasons). I'll just have to cut calories more and try to work out more in my limited free time.

[A_Lurker]

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@2017Resolutions wrote:

Hi! I'm not sure I understand your response. My basic question is whether or not the calories burned shown on the fitbit app is meant to be my TDEE (or, rather, is that the entirety of what my body burns?). If so, I'll have to eat less.

Yes, what fitbit gives you is you entirety of what you are burning each day.  This is you TDEE.  Are you wearing a HR enabled tracker?  Most people find ones without the HR feature underestimates your calories burn a bit, where HR trackers can overestimate.

Sitting 12 hours a day (assuming you sleep too) is going to make it very tough to lose weight, especially if you don't have a lot to lose.  As suggested, find out what your BMR is to make sure you don't eat below it.  See if you can add a few steps during the day on breaks and lunch.  If not you'll need to put in some effort during your limited free hours or in the weekend.

[2017Resolutions]

Thanks for this! Someone posted (in another forum) the calculation for the BMR [BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)]. So this, for me, is around 1500, but if I'm only burning 1,000-1,200 calories a day, it seems like I won't be able to lose the 20 pounds I'm hoping to burn. 

I'm currently in graduate school and work 12 hours a day M-F and 6 hours a day Saturday and Sunday. I'm usually exhausted. I'll just have to cut back on calories (maybe eat more lower-calorie items #veggies) if I can't find more time to go to the gym or walk around.

[Dominique · Accepted solution]

There are several formulas for calculating BMR. The one you have been using is Mifflin St. Jeor (you can see it here). It’s considered one of the more accurate ones and my understanding is it’s also what Fitbit uses. If the formula says your BMR is 1500 (double-check with the calculator in the link I included), it is very unlikely your Fitbit would report 1000-1200 calories burned per day, or you’ve not entered your personal information correctly in Fitbit. Even if you are very sedentary and are hardly moving at all, you should burn more than your BMR.

[2017Resolutions]

Thanks for this! Someone clarified how the fitbit work. I ended up burning over 2000 calories yesterday. It had read 1,000 at mid day and I didn't realize it would increase over the course of the day even if I didn't move. I feel silly, but I learned a lot now.

[Dominique]

All daily stats are reset at Midnight, and a new day starts. When you wake up in the morning, you have already burned a few hundred calories, even if you were sleeping. 

[SunsetRunner]

You could google how many calories would maintain the goal weight you have chosen and select that-I think this method would be the most effective.

[SunsetRunner]

I lost 34 pounds without exercise-most of weigh loss comes from the kitchen, not the gym.  Seated 12 hours is not good, but not insurmountable.  What are you eating?

[2017Resolutions]

All types of things. I eat 1200-1300 calories a day and I weigh everything in my food scale.

[Dominique]

It is generally considered you should eat at least your BMR. You said your BMR was 1500, so you’re eating 200-300 calories below that. Even with minimal exercise, you should still be able to lose weight while eating at your BMR level. Your weight loss will be slower, but you will be losing and the loss will be more sustainable.

If you choose to eat that little (1200-1300), you should focus on food that offer the best bang for your buck: nutritious and filling, but low on calories.

[2017Resolutions]

I'm trying lower because I spent the last two months eating at 1500 and didn't lose a single pound, so I am assuming my BMR is off. I weighed the food and logged it all, so idk what happened. Could be medication I'm on, but I doubt it.

[Dominique]

It could also be the cumulative stress from your studies/work/lack of sleep/prolonged dieting, which results in permanently/chronically elevated cortisol, which itself prevents or slows down weight loss. So it would be a good idea to reduce that stress, by reducing your workload, getting more/better sleep, doing yoga/meditation, eating at a smaller deficit (or even at maintenance, for some time) etc.

Medication can also play a role, but you would know better knowing the actual meds you’re on. Thyroid could also be a factor (have you had it tested)?

At any rate, I would really find the time to move more, as it’s so much easier to lose weight on a higher intake, not to speak of the benefits of exercising on your general health and well-being.

[2017Resolutions]

I had had my thyroid tested. Unfortunately, there's no way for me to cut back on my studies without impacting them. I am going to start working out more regularly (3x a week) so perhaps that will help.

[caveman_06]

Thanks for your answer. I have a followup question on your reply. I had been sedentary all the day and just walked for 30 mins. And my fitbit charge 2 showed I burnt 2600 calories., but my TDEE for sedentary is 1815(http://fitcal.me/tdee for losing weight category). So my question is should I got to eat 1815 on a that day or 2600? Thank you!

[Dominique]

@caveman_06: it’s important to realize that both calculators and your Fitbit make assumptions about your metabolism (based on your age, size etc.); in addition to that, your Fitbit tries to guess your energy expenditure / activity based on the moves of your hand, your HR etc. The numbers they come with are therefore estimates. You should try to assess how close they come to your actual metabolism and energy expenditure. If you’re tracking your intake and weighing yourself, you should be able (after a few weeks) to assess that. Let’s say your Fitbit says you burn 2500 calories in average, you eat 2000 calories (also in average), but you are not losing any weight: this would suggest your Fitbit overestimates expenditure by 500 calories (or it overestimates it by 250 calories, but you also underestimate your intake by 250 calories). Or (using the same numbers) you are only losing at a rate of 0.5 lbs per week: this would suggest a 250 calories discrepancy (which - again - can come from both your Fitbit and yourself).  

[caveman_06]

Thank you. It makes sense. So logging food, tracking the progress across the fitbit estimates would help to give us an idea!

[Baltoscott]

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@caveman_06 wrote:

Thank you. It makes sense. So logging food, tracking the progress across the fitbit estimates would help to give us an idea!

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Yep.  If it turns out that you aren't losing anything after a week or so, try making some more diet changes to lower calories a bit more or move some more throughout the day and reassess in another week.