Impact of extreme obesity on TDEE?
try2again
Posts: 3,562 Member
I was recently in a discussion on a thread with a poster who suggested that a 6' sedentary 400+ lb man would have a TDEE of around 2100 because most TDEE calculators overestimate for people with a high body fat percentage. While I don't find the premise unbelievable that an extremely obese person's TDEE could be skewed a little by their body fat percentage, those particular numbers seem outrageous. I would like to hear if anyone has more knowledge on the subject or could provide reputable links that discuss this?
I would also be interested in the experience of those who have lost extreme amounts of weight and if their calorie allowance + weekly weight loss results bore out the math one way or another.
Thank you in advance
I would also be interested in the experience of those who have lost extreme amounts of weight and if their calorie allowance + weekly weight loss results bore out the math one way or another.
Thank you in advance
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Replies
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The BMR of a 6' 400lbs male at 30 years old is approximately 3268 calories. That's WAY above the TDEE you mention. If that male was somewhat active, that TDEE would be well above 3500 to 4000.
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Strap 250lb of weight to yourself and go about your daily life like that, see if it increases your calorie burn!
It's not just a question of how much energy each pound of tissue consumes for its own maintenance - the sheer size of the body takes extra energy to support, lift and move around.
Your mystery poster is a little out, I think.3 -
I find it impossible to believe a 6' 400+lb man has a lower TDEE than me... Mine is 2300, 5"8 and 150lbs, age 45, sedentary/lightly active.1
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I'm an obese 5'3" female, and have had TDEE higher than that for the last 9 months. I calculate it using my weight loss and CI. My TDEE is always higher than the calculators, MFP, and Garmin. In my experience your poster has it backwards.2
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Christine_72 wrote: »I find it impossible to believe a 6' 400+lb man has a lower TDEE than me... Mine is 2300, 5"8 and 150lbs, age 45, sedentary/lightly active.
Wow, I find it amazing that your TDEE is so high. Yes, you're quite a bit taller than me, but still... I'm about 5"6 1/2 and about 136lbs and only get about 1622. Lets be honest: it's actually closer to 1800 in reality, but still. TDEE envy right here!
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Christine_72 wrote: »I find it impossible to believe a 6' 400+lb man has a lower TDEE than me... Mine is 2300, 5"8 and 150lbs, age 45, sedentary/lightly active.
Wow, I find it amazing that your TDEE is so high. Yes, you're quite a bit taller than me, but still... I'm about 5"6 1/2 and about 136lbs and only get about 1622. Lets be honest: it's actually closer to 1800 in reality, but still. TDEE envy right here!
That number isn't for nothing lol I have to make sure to get at least 14,000 steps (10kms) everyday to keep my TDEE up there.
There were a couple days last week when my family came to stay (sat around yacking the whole time)where i didn't quite hit 3k steps, and my tdee plummeted down to 1670, Which is a stark reminder of what will happen if i ever become very inactive
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At 6'5", 180 pounds my TDEE is 2300. I don't believe it a bit.0
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I saw that post and used that TDEE calculator as well. It gave me a TDEE of between 2000 and 2300 as a 5'3", 114 pound woman and that's almost spot on with my data via Fitbit; sometimes I actually earn more calories than that. I plugged in the stats for that other poster, including the 65% body fat he was assumed to have by the poster who linked the calculator, and got a similar TDEE to my own.
Do I actually believe that's the right TDEE? No. I think there are a lot of factors that go into one's TDEE and it's so hard to pinpoint with calculators. The fact that the poster was assumed to have a body fat percentage of 65% also made the TDEE estimate shoot down by a lot. Changing the body fat percentage to 45% made the TDEE go up by about 900 calories. Yes, obese people have a lot of body fat but they also have a decent amount of muscle underneath that from carrying around all the weight.
However, I do find it interesting because there are a few posters with stats here that are similar to mine, such as @WinoGelato and the two of us always say that Fitbit has been pretty spot on for us with regard to TDEE whereas others who weigh more and/or have a higher body fat percentage claim Fitbit is wildly off. Of course I take that with a grain of salt since most people estimate their food intake, but it makes me wonder if this is related to that in some way.2 -
Christine_72 wrote: »Christine_72 wrote: »I find it impossible to believe a 6' 400+lb man has a lower TDEE than me... Mine is 2300, 5"8 and 150lbs, age 45, sedentary/lightly active.
Wow, I find it amazing that your TDEE is so high. Yes, you're quite a bit taller than me, but still... I'm about 5"6 1/2 and about 136lbs and only get about 1622. Lets be honest: it's actually closer to 1800 in reality, but still. TDEE envy right here!
That number isn't for nothing lol I have to make sure to get at least 14,000 steps (10kms) everyday to keep my TDEE up there.
There were a couple days last week when my family came to stay (sat around yacking the whole time)where i didn't quite hit 3k steps, and my tdee plummeted down to 1670, Which is a stark reminder of what will happen if i ever become very inactive
14k steps is not sedentary/lightly active.
I'm 5'5", 142 lbs, 39, and my sedentary TDEE is 1700. With my usual 15k steps it's a more manageable 2300 as well.
When I was sedentary and obese (214 lbs) my TDEE was about 2100 (supposedly. With the way I ate, it's hard to believe I wasn't 300 lbs).
Whoever told you that, OP, is absolutely clueless, considering as, like someone mentioned, their BMR alone would be way above that...0 -
Maxematics wrote: »I saw that post and used that TDEE calculator as well. It gave me a TDEE of between 2000 and 2300 as a 5'3", 114 pound woman and that's almost spot on with my data via Fitbit; sometimes I actually earn more calories than that. I plugged in the stats for that other poster, including the 65% body fat he was assumed to have by the poster who linked the calculator, and got a similar TDEE to my own.
Do I actually believe that's the right TDEE? No. I think there are a lot of factors that go into one's TDEE and it's so hard to pinpoint with calculators. The fact that the poster was assumed to have a body fat percentage of 65% also made the TDEE estimate shoot down by a lot. Changing the body fat percentage to 45% made the TDEE go up by about 900 calories. Yes, obese people have a lot of body fat but they also have a decent amount of muscle underneath that from carrying around all the weight.
However, I do find it interesting because there are a few posters with stats here that are similar to mine, such as @WinoGelato and the two of us always say that Fitbit has been pretty spot on for us with regard to TDEE whereas others who weigh more and/or have a higher body fat percentage claim Fitbit is wildly off. Of course I take that with a grain of salt since most people estimate their food intake, but it makes me wonder if this is related to that in some way.
Interesting observations- thanks! While I understand fat is not muscle, and thus doesn't require as much energy to sustain, it requires *a lot* of energy to haul around. The idea that this person's TDEE could dip below maintenance level for a 200 lb man seems ludicrous. Everyone I've known that has started off obese and with a high body fat percentage has had a very high calorie allowance to start and lost weight readily. I also found this discussion, which would seem to bear that out:
https://forum.bodybuilding.com/showthread.php?t=1586084130 -
From when I was 220lb to now at 155lbs my TDEE is shockingly close to what it was. I think it's within 300 cals which is pretty damn close for such a wide gap. BMR to BMR the difference is even less. I credit keeping most of my lean mass while I dieted down for this small miracle.0
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This calculator yielded the same results as the post in question. Now my question is, what is a reasonable body fat % for an extremely obese person? If they roughly need to lose half their weight, does that mean their body fat % is 50?
Edit: forgot the link!
https://tdeecalculator.net/0 -
I was recently in a discussion on a thread with a poster who suggested that a 6' sedentary 400+ lb man would have a TDEE of around 2100 because most TDEE calculators overestimate for people with a high body fat percentage. While I don't find the premise unbelievable that an extremely obese person's TDEE could be skewed a little by their body fat percentage, those particular numbers seem outrageous. I would like to hear if anyone has more knowledge on the subject or could provide reputable links that discuss this?
I would also be interested in the experience of those who have lost extreme amounts of weight and if their calorie allowance + weekly weight loss results bore out the math one way or another.
Thank you in advance
I am 60 years old, female, and 5'7". When I started, I was 311 lb and I lost an average of just under 2 lb a week for 3 months eating 1900 calories and being pretty much sedentary (started taking water exercise classes about 2 months in and didn't stat walking for another couple of months). This would put my TDEE at around 2800-2900 calories at the time.
Yes, TDEE calculators can be a bit off but there is no way a 400 lb man would maintain on 2100 calories.
To answer your last question. In my experience, the math worked. I plugged in my stats, set my activity to sedentary, ate back 75% of my exercise calories burned, and lost at my expected rate.
I did err on the conservative side when calculating calorie burn. My water aerobics class is 55 minutes long but I only record 40 minutes because of the amount of time taken up by strengthening and stretching. I swim laps now and record it as "Swimming, leisurely, general" because the calories burned seemed too high for the 1 mph breaststroke I do.1 -
The numbers are based on the differences between TDEE calculators, and I agree with the poster that the body fat calculator is the more accurate one. Here's an illustration (my LBM is roughly 95):
Currently: weight 125, BF% 25; TDEE if sedentary according to different calculators:
Katch-McArdle (uses BF) = 1550
Harris-Benedict (uses weight, height, sex, and age) = 1522
Pretty consistent.
But let's say I'm 225. My lean mass would be greater, but I'd be at a much higher BF%. I'll assume LBM is around 120, which I think is really generous, it's about 25 lb more than current. I'd be at a body fat % of 47. So what are my numbers (again, at sedentary)?
Katch-McArdle says 1850.
Harris-Benedict says 2045.
300 calorie difference.
Now if you are NOT sedentary and if you are conservative about counting back calories (which is how I was when starting -- I was around 200 when I started MFP), then I think the excess calorie count can balance out the overly high TDEE estimate (for example, I claimed to be sedentary when I was really lightly active and lost a bit faster than MFP predicted, but I also did not include that extra active for quite some time).
If you are truly sedentary, as many extremely obese people may be, it's more of an issue.
If you don't count that well, obviously, it can be more of an issue.
If you aim for 1 lb per week instead of 2, obviously more of an issue.
I also found that when I was quite obese (200+) it was EASY to eat at a very sharp deficit (I started MFP at 1250 and had been eating less, not that I'm recommending eating less), and this is why I do generally think that it makes sense for someone quite heavy to aim for 1% of total weight and not merely 1 lb/week UNLESS they are having trouble sustaining.
Anyway, as you get heavier and BF% gets higher, the difference between the scales gets greater.
It is something I think extremely obese people should consider IF they are having trouble losing, and again it's why I think aiming for the 1% is quite reasonable. (I think the person whose thread this started from was eating at more than enough of a deficit, and that his issue had more to do with losing 20 lb in the first two weeks and a 1 week adjustment of water weight being normal.)1 -
53 year old, sedentary, female. I have no idea what my TDEE is, but I keep my NET calories at 1900 and have steadily lost weight from 306 to 279 in 4 months. I can't imagine a 400 lb man NOT losing weight at 2100 calories.
Edit: Got curious and googled a calculator. Showed my BMR at 1951 and my TDEE at 2351. So...yeah. 2100 calories should have him losing weight.1 -
Well as a guy who is 6'5" and about 29%BF, for now, and weighs in at 280 I have ~199 lean lbs. Of course that includes the bone and the other stuff.
I just went to the TDEE calc and it is indicating my maint numbers at my current weight, with light workouts is: 3180 cal/day. OH MY!
If I ate that much in any given day I would be like 400lbs,
Here is the question I have about all of this. Lets just say the calc is spot on and the macro's needed are correct. At my size on a low carb diet I am told I should consume ~260 grams of protein a day. Knowing the body can only process so much protein per meal, say 40ish grams, this means I would need 6 meals per day with 40gr of protein each. THATS a lot of food, like 6 chicken breasts, or 3 shakes and 3 breasts etc EVERY DAY..... wow. This is just to maintain.
I also find it interesting how the calculators will tell me how much I'm supposed to weigh ~195-207 SERIOUSLY! Oh and the theoretical max for muscle is 211lbs. So without any effort I am within 5% of my max potential, again SERIOUSLY......
This is why I don't like the calc's. They may provide a starting point for a journey, but surely shouldn't be considered gospel.0 -
If this were true, MFP's calorie allowance for 2 lbs/week loss for obese, sedentary people would be completely off. If it credited them with a TDEE of 3500 and gave them a calorie allowance of 2500 to lose 2 lbs/week, they wouldn't lose *anything*. With the huge volume of "why aren't I losing weight?" posts, I haven't seen any with this complaint.
I really don't know what to make of this.
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Strap 250lb of weight to yourself and go about your daily life like that, see if it increases your calorie burn!
It's not just a question of how much energy each pound of tissue consumes for its own maintenance - the sheer size of the body takes extra energy to support, lift and move around.
Your mystery poster is a little out, I think.
I'm the mystery poster in question. Left out of the description was that's the TDEE for a person of that size who is sedentary and does no physical activity. At that size, yes, even walking starts to burn meaningful amounts of calories.
At that size, we're talking about a body that is around 65% body fat. Plug that into Katch-McCardle, instead of using the base assumptions of TDEE formulas that don't account for body composition, and go...scottyp65 wrote:This is why I don't like the calc's. They may provide a starting point for a journey, but surely shouldn't be considered gospel.
I agree! It's good to have a reasonable starting point, but ultimately the way to figure this out is through personal logging history. It was about six months into my own journey, a few years back, that I realized what the numbers were telling me...BMR remained nearly constant through many, many pounds of weight loss, because my lean body mass was remaining constant.1 -
This calculator yielded the same results as the post in question. Now my question is, what is a reasonable body fat % for an extremely obese person? If they roughly need to lose half their weight, does that mean their body fat % is 50?
Edit: forgot the link!
https://tdeecalculator.net/
Higher. Don't forget, there's a BF% at the end of the "need to lose" phase. So if you drop from 400 to 200, you've lost half, but are still at (pick a number) 20% BF.
Typically, a 6 foot person at 300 pounds will be ~50%, and at 400 pounds around 65%. At these levels round numbers are more than fine, more accuracy than that isn't needed.0 -
This calculator yielded the same results as the post in question. Now my question is, what is a reasonable body fat % for an extremely obese person? If they roughly need to lose half their weight, does that mean their body fat % is 50?
Edit: forgot the link!
https://tdeecalculator.net/
Higher. Don't forget, there's a BF% at the end of the "need to lose" phase. So if you drop from 400 to 200, you've lost half, but are still at (pick a number) 20% BF.
Typically, a 6 foot person at 300 pounds will be ~50%, and at 400 pounds around 65%. At these levels round numbers are more than fine, more accuracy than that isn't needed.
I appreciate you joining the discussion, as obviously I'm open to the idea that I don't know all there is to know about the topic. I also appreciate the point that the "sedentary" aspect is what's critical here.
Do you have links to sources/studies that discuss this? (I don't ask as a challenge, but because I'd genuinely like to read more about it and haven't been able to find anything in a casual search.)
This still bothers me as it applies to practical application. As with the poster in question, with a calculated TDEE of 2100, he would be looking at a calorie allowance of 1000 just to lose 2 lbs/week, maybe 1500 if he adds walking, as you say. That just doesn't seem to match up with the many posts I've seen where the poster is on a minimum calorie allowance (1500 for men) and consistently losing 4-5 lbs/week for several months.0
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