TDEE not accurate?

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  • CollieFit
    CollieFit Posts: 1,683 Member
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    Simon hit it right on the head -- exactly what I was going to say. To calculate your TDEE using your actual data, you need to first make sure that you have been logging EVERYTYHING. Then choose two points in time with weight measurements, say the 1st and 7th of the month, as an example. During those 7 days, you lost one pound. And during those 7 days, you averaged 1550 calories intake of food per day. That means you ate a total of 10850 calories. Add that to the 3500 calories lost (1 pound of weight loss). Your total calories consumed, hence your TDEE is (10850 + 3500) / 7 = 2050. Is that clear? If you have any questions, please ask. I calculate my own TDEE. It's the only way to get an accurate reading. The online sources are okay but they are gross approximations at best anyway.

    Interesting...

    I did the calculation doing the formula which gave me a TDEE of 1763...

    This is quite close to the Scooby score of 1706 but quite a way off the IIFYM score of 1867.
  • emjaycazz
    emjaycazz Posts: 330 Member
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    I think for me, the biggest problem with the on-line calculators is the "fuzzy" definitions, especially on the exercise front. Take 2 people who "work out 3 days a week". One does light resistance training and some cardio 3 times a week. The other goes on 100 plus mile bike rides 3 times a week. They both fit the same category and both might make the choice. But they hardly are burning the same number of calories during those 3 workouts. Not even close. And that is why calculating your own TDEE based on your own data is clearly the best option. Assuming your food diary is logging everything. The more accurate your food diary, the more accurate your TDEE calculation will be.

    I've always wondered this whenever I go and input my activity level in any TDEE calculator--for me, being 5'1 (and now 100 lbs I feel like I have to be accurate). Ironically, I just did the average over 32 days per Lee's suggestion--and that TDEE is actually 10 calories away from the IIFYM estimate!
  • cwolfman13
    cwolfman13 Posts: 41,874 Member
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    IIFYM calculates TDEE at 1550, so still under. Why are Scooby's calc and IIFYM's so different?!

    My diary is open to friends. I weigh what I eat on a dig scale, I log everything.

    I work out about 3 times a week with varying intensity so would rather work out my desk job TDEE and then eat extra workout cals.

    When you do TDEE, you're supposed to include all of your activity...that seem incredibly low, especially for someone who works out. If it is, you might want to get some blood work done...possible medical issue or vitamin deficiency going on there. The average female who just goes about her day maintains on roughly 1800 - 2000 calories per day.

    Also, a 250 calorie deficit from TDEE is only about 1/2 Lb per week...given that scales are hardly accurate to a whole number, they are even more inaccurate when you're talking fractions...add to that normal body weight fluctuations, and 1/2 Lb loss is almost impossible to see on the scale in the short term. When I was losing 1/2 Lb per week, I really had to look at it in 4-6 week trends to see anything.
  • HeidiCooksSupper
    HeidiCooksSupper Posts: 3,831 Member
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    TDEE is always an estimate. Each of us has a different body composition. Some are heavy boned, some are fine boned. We carry around different amounts of water, fat, and lean tissue. Our heart rates vary. Calculations of calories in foods are estimates based on estimates and assumptions. Our measurements are not scientifically precise. So, you and I may enter the same figures into a TDEE calculator and get the same result but that TDEE estimate may be high for you and low for me or vice versa.

    That being said, using estimates is better than not using them. You will only know what works for you by finding it. If you are trying to maintain but are still losing, your TDEE estimate may be low. If you are trying to maintain but are gaining, your TDEE estimate may be high.
  • madtownjeremy
    madtownjeremy Posts: 249
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    Try the calc on here: http://iifym.com/iifym-calculator/

    I havent lost much in while and I think my calories were too low, now im upping it too see if it makes a difference.

    I can personally attest to the calculators at this site. I upped my cals to these suggestions and it helped me bust through. It also almost perfectly matched what my bodymedia told me I was already doing.
  • Snow3y
    Snow3y Posts: 1,412 Member
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    Yeah don't bother using mfp's calculator.. it's pretty useless+ inaccurate. Just use another site.. Use MFP for tracking only
  • highervibes
    highervibes Posts: 2,219 Member
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    Remember though that you can calculate TDEE from your actual calorie intake over time needed to maintain but you can only estimate using the various web sites like Scooby's, IIFIYM etc.

    Could you explain this further please Si?

    Simon hit it right on the head -- exactly what I was going to say. To calculate your TDEE using your actual data, you need to first make sure that you have been logging EVERYTYHING. Then choose two points in time with weight measurements, say the 1st and 7th of the month, as an example. During those 7 days, you lost one pound. And during those 7 days, you averaged 1550 calories intake of food per day. That means you ate a total of 10850 calories. Add that to the 3500 calories lost (1 pound of weight loss). Your total calories consumed, hence your TDEE is (10850 + 3500) / 7 = 2050. Is that clear? If you have any questions, please ask. I calculate my own TDEE. It's the only way to get an accurate reading. The online sources are okay but they are gross approximations at best anyway.

    ^ except you should use the data from at least a month, and not your first month either.
  • sanndandi
    sanndandi Posts: 300 Member
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    Also, a 250 calorie deficit from TDEE is only about 1/2 Lb per week...given that scales are hardly accurate to a whole number, they are even more inaccurate when you're talking fractions...add to that normal body weight fluctuations, and 1/2 Lb loss is almost impossible to see on the scale in the short term. When I was losing 1/2 Lb per week, I really had to look at it in 4-6 week trends to see anything.

    This exactly. I am at a 1/2 lb per week loss now that I am within 10 lbs of my goal weight. It was very hard to see progress on the scale given the natural weight fluctuations and scale inaccuracies. I am now doing monthly weigh-ins and as long as the trend is going in the right direction I am happy. Yes, it's slow and sometimes frustrating but that's how it is. And also, thanks for those links & explanations. I'm going to try to figure out my TDEE using my own numbers.
  • OhFitness
    OhFitness Posts: 31 Member
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    TDEE is just an educated guess. Everyone is different, so you have to tweak it for you. I prefer tracking body fat and not depending as much on the scale. Body fat is tracked about once a month. That way you know if your nutrition is really working (i.e. muscle loss or fat loss).
  • Fit_Fox88
    Fit_Fox88 Posts: 410 Member
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    Remember though that you can calculate TDEE from your actual calorie intake over time needed to maintain but you can only estimate using the various web sites like Scooby's, IIFIYM etc.

    Could you explain this further please Si?

    Simon hit it right on the head -- exactly what I was going to say. To calculate your TDEE using your actual data, you need to first make sure that you have been logging EVERYTYHING. Then choose two points in time with weight measurements, say the 1st and 7th of the month, as an example. During those 7 days, you lost one pound. And during those 7 days, you averaged 1550 calories intake of food per day. That means you ate a total of 10850 calories. Add that to the 3500 calories lost (1 pound of weight loss). Your total calories consumed, hence your TDEE is (10850 + 3500) / 7 = 2050. Is that clear? If you have any questions, please ask. I calculate my own TDEE. It's the only way to get an accurate reading. The online sources are okay but they are gross approximations at best anyway.

    Do you calculate using the total number of calories you ate per day (including exercise) or only the actual food calories that you ate?
  • JoRocka
    JoRocka Posts: 17,525 Member
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    And it is a constant re-evaluation. It isn't like it is number set in stone. Every few weeks or a month or so I'll recalculate it. It is a lagging indicator, but it is by far more accurate than the on-line calculators. And it will put you no further than a hundred calories or so per day away once you get near maintenance. Just re-evaluate based upon current data.

    this.

    it drives me insane when people are like well this is what it was and now X, Y and Z. I'm like- did you lose mass? get fitter? work out harder? like what's been changing?

    gotta re-evaluate. nothing is set in stone except the formula.
  • sijomial
    sijomial Posts: 19,811 Member
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    Do you calculate using the total number of calories you ate per day (including exercise) or only the actual food calories that you ate?

    Think you are confusing the MFP versus TDEE diet methods. This is simply the way to back calculate your TDEE.

    Imagine it as a balance:
    On one side all the calories you eat or drink. On the other side of the balance your BMR plus non-exercise activity plus your exercise (a.k.a. TDEE, everything that consumes calories).
    So because you track your calorie input and you are maintaining your weight you are in balance and the two sides are equal.
  • Mr_Knight
    Mr_Knight Posts: 9,532 Member
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    Remember though that you can calculate TDEE from your actual calorie intake over time needed to maintain but you can only estimate using the various web sites like Scooby's, IIFIYM etc.

    Could you explain this further please Si?

    Simon hit it right on the head -- exactly what I was going to say. To calculate your TDEE using your actual data, you need to first make sure that you have been logging EVERYTYHING. Then choose two points in time with weight measurements, say the 1st and 7th of the month, as an example. During those 7 days, you lost one pound. And during those 7 days, you averaged 1550 calories intake of food per day. That means you ate a total of 10850 calories. Add that to the 3500 calories lost (1 pound of weight loss). Your total calories consumed, hence your TDEE is (10850 + 3500) / 7 = 2050. Is that clear? If you have any questions, please ask. I calculate my own TDEE. It's the only way to get an accurate reading. The online sources are okay but they are gross approximations at best anyway.

    This...so this.

    I used that calculation too...over a 1 month period and follow that number...and as I lose weight adjust based on actuals.

    http://www.myfitnesspal.com/groups/home/10118-eat-train-progress

    Ditto! I also add in BF% tracking so I can follow changes in LBM as well. And by tracking all exercise, I can break down TDEE further into "exercise" and "daily routine" categories, and get an even tighter read on what is actually happening.
  • mebepiglet123
    mebepiglet123 Posts: 327 Member
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    Just keep increasing theses calories until you find your sweet spot......
  • mwooderson
    mwooderson Posts: 254 Member
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    IIFYM calculates TDEE at 1550, so still under. Why are Scooby's calc and IIFYM's so different?!

    My diary is open to friends. I weigh what I eat on a dig scale, I log everything.

    I work out about 3 times a week with varying intensity so would rather work out my desk job TDEE and then eat extra workout cals.

    I just tested IIFYM's calculator vs. Scooby's using the Mifflin... method and they were 3 calories off which is really good! Scooby allows for several different method calculations to be used and they will very widely.
  • heybales
    heybales Posts: 18,842 Member
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    Do you calculate using the total number of calories you ate per day (including exercise) or only the actual food calories that you ate?

    Didn't you just say the exact same thing, really?

    I know where you are confused, but it's total eaten.

    It' merely going back to the basic fact of weight loss, you must eat less than you burn.

    Merely re-arranging the formula to arrive at what you burn, based on weight loss amount. Actually, it's assuming you only lost fat weight at 3500 cal per pound.

    Do your diet wrong, and that's not a good assumption, nor does the math hold up when you lose muscle mass or LBM, instead of fat mass.
  • kimmyt4
    kimmyt4 Posts: 18
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    Just had a question for all who has been doing this for a while.

    I just started doing TDEE -20% last week. I am wondering how long it will be before I start to see changes in the scale?

    I am 34, female, 63 inches, 193 lbs. I work out on an elliptical for about 30-40 minutes 3 - 4 times per week as well as do some kettle bell exercises using a 10 lbs kettle bell.

    I have used both Scooby and IIFYM calculators for Mifflin and they are pretty close. my BMR on Scooby is 1547, TDEE is 2128 based on 1-3 hours of exercise per week with mostly a desk job during the day. 20% cut is 1702
    IIFYM BMR is 1562. with the same info as above my TDEE is 2148 and 20 % cut is 1718.

    I guess I should be expecting a 4-6 week wait to see if this will work?
  • highervibes
    highervibes Posts: 2,219 Member
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    Just had a question for all who has been doing this for a while.

    I just started doing TDEE -20% last week. I am wondering how long it will be before I start to see changes in the scale?

    I am 34, female, 63 inches, 193 lbs. I work out on an elliptical for about 30-40 minutes 3 - 4 times per week as well as do some kettle bell exercises using a 10 lbs kettle bell.

    I have used both Scooby and IIFYM calculators for Mifflin and they are pretty close. my BMR on Scooby is 1547, TDEE is 2128 based on 1-3 hours of exercise per week with mostly a desk job during the day. 20% cut is 1702
    IIFYM BMR is 1562. with the same info as above my TDEE is 2148 and 20 % cut is 1718.

    I guess I should be expecting a 4-6 week wait to see if this will work?

    Unless you've been really low for a while calorie wise you should see something in the next week or 2. What were you "doing" before?
  • ndj1979
    ndj1979 Posts: 29,139 Member
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    Your TDEE should include exercise but I get the impression you aren't including it hence the low number?

    Remember though that you can calculate TDEE from your actual calorie intake over time needed to maintain but you can only estimate using the various web sites like Scooby's, IIFIYM etc.

    this...

    Calculators are just that, calculators that estimate what your TDEE. There is no way that an online calculator Is going to accurately predict the TDEE for every person..

    What you really need to do is use trial and error with your scale. I weight myself three times a week at the same time, and then take a weekly average to account for any fluctuations. I have pretty much found that I lose at around 2000 to 2100 cals a day and maintain at around 2400 to 2500 start to gain at anything over 2500....this is really the most accurate way to figure this out.

    If you are gaining the calculators have either calculated your TDEE wrong or you are under estimating calories....
  • stealthq
    stealthq Posts: 4,298 Member
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    As I neared my goal I've increased calories slightly (from 1300 to 1400) but am now not losing at all even though I'm still eating 250cal a day below what I have worked out as maintenance (1660)

    It has only been 3 weeks, which I appreciate is not a plateau yet but I'm no longer convinced that TDEE is right, maybe my maintenance is much lower than expected? Or am I just having a little rut/slow down?

    How close are you to maintenance, and were you losing at the rate you expected based on your deficit before? While everything regarding the inaccuracy of estimates, etc, mentioned by the previous posters is true, there is also the possibility that you just haven't waited long enough for your body to adjust to your new intake.

    I was originally losing at exactly the rate I should have been based on my deficit from calculated TDEE. Then I raised my calories to a deficit of 250 as I got closer to my original goal, like you did. Had a month with no weight loss. Then without changing anything, suddenly dropped 2 lbs, putting me back at the expected rate of loss. I continued losing at a lb every 2 wks. Now I'm losing about a lb a month, but I've also cut out the regular walking I'd been doing, so that explains that.

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