tag:blogger.com,1999:blog-8859456735165996893.post4235173665234018689..comments2024-03-28T02:36:04.078-07:00Comments on Health Correlator: Kleiber's law and its possible implications for obesityNed Kockhttp://www.blogger.com/profile/02755560885749335053noreply@blogger.comBlogger20125tag:blogger.com,1999:blog-8859456735165996893.post-7596458310685679942012-06-29T11:28:50.081-07:002012-06-29T11:28:50.081-07:00that more useful information thanks for sharingthat more useful information thanks for sharingonline bookiehttp://www.priceperheadcostarica.com/betting-software-services/noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-84939127464263263262012-01-31T19:38:13.033-08:002012-01-31T19:38:13.033-08:00I see ! and that's an interesting study, thank...I see ! and that's an interesting study, thanks again Ned. <br />Spurs thought> I wonder if we know whether a formerly obese person's composition has changed yet again on losing weight, that is, Not back to the original composition. Vague recollections of 'slow twitch muscle fibers' more efficient than 'fast' ones and building up slow ones to help carry/move extra weight. But then, that circles back to some degree of 'system adaptation' I guess :-) That would take time indeed to readjust (maybe with HIIT or Tabata for fast twitch -I wonder...).mariehttps://www.blogger.com/profile/08667581634650513221noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-44061772526931226792012-01-31T19:11:52.049-08:002012-01-31T19:11:52.049-08:00Hi MC.
> a lb.of fat at rest burns ~3 calo...Hi MC.<br /><br /> > a lb.of fat at rest burns ~3 calories per day, while a lb.of muscle ~6 calories (some texts say 2 and 5, but I'm choosing the easier ratio!)<br /><br /> Well, with a difference of 3 calories per lb, times 60 (210-150), would give 180 calories per day. That is a bit less than the 206 calories per day from Kleiber's law.<br /><br /> It is possible, but we still have studies like Astrup et al.’s suggesting that the metabolism of the formerly obese is slower.Ned Kockhttps://www.blogger.com/profile/02755560885749335053noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-91396154158392341872012-01-31T19:04:46.929-08:002012-01-31T19:04:46.929-08:00Hi Sam. Stephan is right about that, as he is abou...Hi Sam. Stephan is right about that, as he is about many things. The main reasons are those mentioned by johnnyv, along with others, such as a limit on what someone can eat. (Even that guy in the Monty Python movie exploded after too much eating; clear scientific proof that there such a limit!)<br /><br /> In fact, the megafat are somewhat rare, and often quite resistant to complications that are associated with lipotoxicity, including type 2 diabetes. Unlike most of us, the fat cells of the megafat take much longer to become insulin resistant.Ned Kockhttps://www.blogger.com/profile/02755560885749335053noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-81694469131710216802012-01-31T18:28:58.297-08:002012-01-31T18:28:58.297-08:00Thanks for liking that Ned ;-) My area is, oh so c...Thanks for liking that Ned ;-) My area is, oh so coincidentally, physical chemistry. However right now, I'm just a dog with a bone, can you help me out? I remember the 'bust' about how much more energy muscle burns vs.fat and that no, you don't burn a whole lot more calories a day just by building up muscle. Yet, bear with me here : a lb.of fat at rest burns ~3 calories per day, while a lb.of muscle ~6 calories (some texts say 2 and 5, but I'm choosing the easier ratio!). Now, if someone gains weight, they change their fat % quite a bit (eg. at normal weight they may be 25% fat, but when obese they'd be 45% fat, or 50% or more...). Now they have More of their body (eg.45%) burning at the lower calorie rate (3 kC/lb/day). So their total expenditure would not scale linearly with their weight. Right? This of course is at rest. Once they move, things change dynamically because it takes more energy to move the extra weight. <br />I was just wondering if it's possible to model this? And does it seem like this difference in body composition may be a significant factor in the change in energy expenditure of the obese? In which case there wouldn't be a long adjustment period after weight loss (looking to give my overweight cousin some hope, she saw that recent NY Times article!)mariehttps://www.blogger.com/profile/08667581634650513221noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-6536318666255801552012-01-31T13:56:48.790-08:002012-01-31T13:56:48.790-08:00Re: Sam Nox
Seems like the "plateau" wo...Re: Sam Nox<br /><br />Seems like the "plateau" would more likely be due to filling current fat cells to maximum capacity so that they leak triglycerides despite of high insulin levels.<br /><br />Suddenly there is more fat available for energy production until the number of fat cells increases again.<br /><br />Then when you lose all that weight back to your original(if at all possible) you have more fat cells with less fat per cell so way less leptin production.<br /><br />If only it was as easy to have those extra fat cells die off as it was to produce new ones.johnnyvnoreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-72809695770506558692012-01-31T11:59:39.315-08:002012-01-31T11:59:39.315-08:00Application of Kleiber’s law to fat gain (implied ...Application of Kleiber’s law to fat gain (implied in your analysis) leaves me blurry-eyed. Nick Lane presents a very good and interesting analysis in Power, Sex, Suicide. According to Lane, the ¾ exponent only holds across a wide range of species but not within species, where it varies widely; ie ¾ is an artefact. Original work done with dogs supports a 2/3 scaling. Lane analyses the question in terms of metabolism not networks (per the Sante Fe thinking) and indicates variation of the scaling with the metabolic activity of particular tissue eg active tissue like muscle scales more closely to 1. Overall it seems that ¾ is a reasonable number but for the wrong reasons. Extrapolation to fat gain seems like quite a stretch.Morrishttps://www.blogger.com/profile/11490835915837052199noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-3234731600207665682012-01-31T11:17:23.996-08:002012-01-31T11:17:23.996-08:00Ned,
Not to pick on Stephan Guyenet, but he once ...Ned,<br /><br />Not to pick on Stephan Guyenet, but he once told me in a comment reply that people stop getting fat when energy expenditure rises to equal intake:<br /><br /><b>"As body mass increases, energy expenditure increases, so you will not keep gaining fat mass indefinitely. A person will reach a plateau when energy intake matches expenditure."</b><br /><br />Kleiber's Law clearly precludes this from happening by an increase in BMR, and I don't know of any evidence that the overweight or obese spontaneously engage in increased levels of physical activity, although they may do so as a part of a weight-loss program.<br /><br />Your (or anyone else's) thoughts?Sam Knoxhttps://www.blogger.com/profile/15632591648777098250noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-80496556348958800192012-01-31T07:47:22.816-08:002012-01-31T07:47:22.816-08:00"evidence that a lower metabolic rate increas..."evidence that a lower metabolic rate increases longevity"<br /><br />or even <br /><br />"that longevity lowers metabolic rate"<br /><br />Either way it might be conjectured that mouse-seconds tick faster than whale-seconds in terms of how many caesium atom vibrations contribute to either!!<br /><br />Ahh - the mysterious milieu interieur.<br /><br />SlainteLeonRoverhttps://www.blogger.com/profile/01484097018449402128noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-17336800128186287402012-01-30T19:09:29.411-08:002012-01-30T19:09:29.411-08:00By the way, bigger animals generally tend to live ...By the way, bigger animals generally tend to live longer than smaller ones, which some have taken as evidence that a lower metabolic rate increases longevity.<br /><br /> But I don’t think this is the cause of the overweight-longevity paradox:<br /><br /> http://jama.ama-assn.org/content/298/17/2028.fullNed Kockhttps://www.blogger.com/profile/02755560885749335053noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-17281628718807582112012-01-30T19:04:44.982-08:002012-01-30T19:04:44.982-08:00Hi Marie, thanks. Well, there was a lot of talk a ...Hi Marie, thanks. Well, there was a lot of talk a while ago about muscle burning a lot of energy, way more than fat. It turned out not to be true.<br /><br /> “Marie Curious” eh? I like that.Ned Kockhttps://www.blogger.com/profile/02755560885749335053noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-13898245709762066212012-01-30T19:02:19.075-08:002012-01-30T19:02:19.075-08:00Hi Leon. Smaller bodies tend to dissipate more ene...Hi Leon. Smaller bodies tend to dissipate more energy than bigger ones, which is in part due to the higher surface-volume ratio that Paul and Chase referred to.Ned Kockhttps://www.blogger.com/profile/02755560885749335053noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-41368124762473602372012-01-30T18:57:33.461-08:002012-01-30T18:57:33.461-08:00Hi Paul. Yes, much of the thinking behind the law ...Hi Paul. Yes, much of the thinking behind the law relies on the surface to volume ratio, but that doesn’t agree as well with the data as the 3/4. There are exceptions to the latter as well. As for the inertia, many studies suggest that it exists, compounding the lower metabolic rate associated with lower weight.Ned Kockhttps://www.blogger.com/profile/02755560885749335053noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-63598632092442172882012-01-30T15:37:10.679-08:002012-01-30T15:37:10.679-08:00Hi Ned, your posts often bring concepts into the n...Hi Ned, your posts often bring concepts into the nutrition discussion that I don't see anywhere else and I thoroughly enjoy them. Could you help me better understand your reasoning in this one? It seems critically based on your statement that "It is unreasonable to assume that the extra mass itself has a significantly lower metabolic rate,...". Why do you think it unreasonable? Or rather, why unreasonable if we're talking about the same individual at two weights? I though that the mass an obese person accumulates is Mostly Fat (not Mostly muscle, or organ or bone...) or is that just a common fallacy? If however it Is indeed mostly fat, could you calculate if the energy expenditure difference per pound of fat vs.pound of muscle is enough to account for the apparently better efficiency of the same person in the obese state? Is that even possible?<br />Thanks for considering this!mariehttps://www.blogger.com/profile/08667581634650513221noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-76541029821682607682012-01-30T09:46:43.171-08:002012-01-30T09:46:43.171-08:00Hey Ned.
Mike Eades had a blog on this Sept 2009
...Hey Ned.<br /><br />Mike Eades had a blog on this Sept 2009<br /><br />http://www.proteinpower.com/drmike/low-carb-library/are-we-meat-eaters-or-vegetarians-part-ii/<br /><br />He reproduces Kleiber's hand drawn data on log-log paper. There are two other annotated lines Weight and Surface bounding the data, but with no indication as to the significance.<br /><br />My copy of McArdle,Katch^2 (pub. 2000) contains reference to Cunningham FFM (fat free mass), Harris & Benedict (body mass, height and age). There is, in addition, a nomogram which calculate BSA ( body surface area) from an equation which has the form<br /><br />BSA= const X height^0.725 X body-mass^0.425 <br /><br />multiply this by a emissivity rate which varies by age and gender to derive an RDEE (BMR).<br /><br />This is a mess! Particularly as nowhere is a mention of standard errors of estimation, or any of those nice things which data nerds with a background in AOV like to see. (Which reminds me that Staffan Lindeberg's AHS presentation on Youtube includes some of the best graphical data plots I have come across. McArdle,Katch^2 have a lot to learn.)<br /><br />One intriguing question springs to my thermodynamically educated mind - have any studies been done on the basal temperatures of these mites and giants? I am minded to ask as Petro HyperVet has recently mentioned that "little furry rodents" are inordinately warm!<br /><br />Mind you, once one discusses emissivity rates & temperatures, one is into Thermo Law 2 and Entropy . . . . Hmmmm<br /><br />SlainteLeonRoverhttps://www.blogger.com/profile/01484097018449402128noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-55982404468439128802012-01-30T09:12:51.037-08:002012-01-30T09:12:51.037-08:00Since my initial comment was directed at Paul, I s...Since my initial comment was directed at Paul, I should have said "the narrative that Ned describes".Chase Saundershttps://www.blogger.com/profile/18367661066053842171noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-50888957035660557732012-01-30T09:11:08.646-08:002012-01-30T09:11:08.646-08:00Good point, Paul, and I think it's correct re:...Good point, Paul, and I think it's correct re: 2/3 of the 3/4. Much is written in biology about the surface area to volume ratio, so someone may have quantified head loss, but I would have to guess it's proportionate. <br /><br />Still, the gap is 8%. From a metabolic perspective this is still huge and may well fit with the narrative you describe. It's fascinating to think this could quantify the adaptive response of an organism to it's particular point in the surface area to volume continuum.Chase Saundershttps://www.blogger.com/profile/18367661066053842171noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-5468179406641292412012-01-30T08:33:29.392-08:002012-01-30T08:33:29.392-08:00Oh, I am done trying to model it! As I get older,...Oh, I am done trying to model it! As I get older, I do notice more and more: thyroid function = f(energy expenditure). I can almost hear the machinery grinding up or down, the correlation very high. So, reducing diets (or increasing diets, as long as I say "fixed" from the leptin reset) are toast.Exceptionally Brashhttps://www.blogger.com/profile/13177479330600606059noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-74006650307293275872012-01-30T08:00:01.520-08:002012-01-30T08:00:01.520-08:00I would also wonder how the composition of the bod...I would also wonder how the composition of the body weight affects metabolism post weight loss. Going from obese to lean often involves loss of LBM (especially if bad diet and/or exercise -- read cortisol-inducing chronic cardio a la Biggest Loser is the mechanism). <br /><br />It may just be wishful thinking on my part, but I'm hoping that eating the right diet and doing the right kind of exercise not only minimizes LBM but also sends the right kinds of signals to actually help improve metabolism.Beth@WeightMavenhttps://www.blogger.com/profile/17725838221780385439noreply@blogger.comtag:blogger.com,1999:blog-8859456735165996893.post-31406099986997534572012-01-30T05:46:54.828-08:002012-01-30T05:46:54.828-08:00Hi Ned,
I would have thought a major factor in Kl...Hi Ned,<br /><br />I would have thought a major factor in Kleiber's law would be the surface area to volume ratio, which would lead to something close to a 2/3 exponent, not far from 3/4. Then I could see other factors, like compensatory adaptations, moving the exponent to what is observed.<br /><br />If that's the case, then most of the change in energy expenditure in the obese should be recovered as the weight is lost, not with a long adjustment period. So it looks to me like the process of weight loss, rather than obesity itself, is more like to be inducing a reduced metabolic rate.Paul Jaminethttps://www.blogger.com/profile/15122941682076992645noreply@blogger.com