Comments on: How is a steady-state weight calculated?
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated/
Comments on Ask MetaFilter post How is a steady-state weight calculated?Sun, 29 Jun 2008 19:36:30 -0800Sun, 29 Jun 2008 19:36:30 -0800en-ushttp://blogs.law.harvard.edu/tech/rss60Question: How is a steady-state weight calculated?
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated
I am A years old, am H inches tall and I weigh W pounds. I burn a total of B calories per day on average (that's including exercise as well as just daily living and sleeping). I consume E calories per day. What would my steady-state weight be expected to be, and how long would it take to reach it?post:ask.metafilter.com,2008:site.95356Sun, 29 Jun 2008 19:18:57 -0800zaebizweightfitnessfatbodymetabolismBMRcaloriesBy: Justinian
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392032
Obviously this would be a very crude esimate anyway, but you can't even get that without knowing your sex. Basal metabolic rate depends heavily on if you are male or female.comment:ask.metafilter.com,2008:site.95356-1392032Sun, 29 Jun 2008 19:36:30 -0800JustinianBy: chrisamiller
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392035
Your question is flawed. There's steady state to be reached, unless B always equals E. <br>
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If you consistently consume more calories than you burn, you'll gain weight more or less indefinitely (see <a href="http://www.foxnews.com/story/0,2933,330542,00.html">the 1200 pound man</a> for an example). If you burn more than you consume, you'll be a little more limited by bone structure and stuff, but if you consistently run that deficit, you'll become malnourished, fall ill, and die.<br>
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Here's a little info that will help you do the math, though:<br>
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A net gain of 3500 calories is about a pound of weight gain. (give or take a little)<br>
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So, daily weight change = (E-B)*3500<br>
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(Height is irrelevant in this simplified calculation.)comment:ask.metafilter.com,2008:site.95356-1392035Sun, 29 Jun 2008 19:37:05 -0800chrisamillerBy: orange swan
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392036
<i>Basal metabolic rate depends heavily on if you are male or female.</i><br>
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I'd amend that to read "depends heavily on what percentage of your weight is muscle and what percentage is fat". Muscle burns more calories than fat, therefore men, who tend to be more muscular, usually burn more calories as a result.comment:ask.metafilter.com,2008:site.95356-1392036Sun, 29 Jun 2008 19:38:53 -0800orange swanBy: ssg
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392037
Your weight will increase whenever E is greater than B and will only be steady when E = B. You need to know how B varies with W (presumably, when you are heavier you will burn more calories per day). Are you asking someone to approximate the relationship between B and W?comment:ask.metafilter.com,2008:site.95356-1392037Sun, 29 Jun 2008 19:40:28 -0800ssgBy: Justinian
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392040
chrisamiller: You can actually come up with a crude formula if we know the sex of the person involved because your resting burn rate for calories increases as your weight increases, so if E is constant as the question indicates, B will eventually equal E as weight increases. Obviously depending on the initial values of B and E this could either be very quickly or not until the person is the size of the goodyear blimp.<br>
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I'm assuming this is some sort of abstract math problem and not asked in expectation of a real-world answer, because I agree looking for a real-world answer is doomed to failure.comment:ask.metafilter.com,2008:site.95356-1392040Sun, 29 Jun 2008 19:42:12 -0800JustinianBy: lukemeister
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392048
From a <a href="http://www.bmi-calculator.net/bmr-calculator/bmr-formula.php">Basal Metabolic Rate (BMR) calculator</a>:<br>
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Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) - ( 4.7 x age in years )<br>
Men: BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) - ( 6.8 x age in year )<br>
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Then <a href="http://www.bmi-calculator.net/bmr-calculator/harris-benedict-equation/">multiply by BMR by a factor between 1.2 and 1.9</a>, depending on whether you're a slug or Speedy Gonzales.comment:ask.metafilter.com,2008:site.95356-1392048Sun, 29 Jun 2008 19:47:03 -0800lukemeisterBy: Justinian
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392059
Enh, since this is so crude and inaccurate anyway, I'm going to assume you're asking about a dude. X = calories burned from exercise. I don't see how you lump all "calories burned" together and still get a meaningful answer.<br>
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B = 66 + 6.23W + 12.7H - 6.8A + X<br>
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Steady state weight achieved when B = E<br>
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So E = 66 + 6.23W +12.7H - 6.8A + X<br>
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W = (E - X - 12.7H +6.8A - 66) / 6.23comment:ask.metafilter.com,2008:site.95356-1392059Sun, 29 Jun 2008 19:52:30 -0800JustinianBy: Justinian
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392061
I want to reiterate that this treats your question like a theoretical math problem and I have absolutely zero confidence in the real world application of this formula.comment:ask.metafilter.com,2008:site.95356-1392061Sun, 29 Jun 2008 19:55:36 -0800JustinianBy: zaebiz
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392143
I was thinking more like - the more I weigh, the more food I need to consume to maintain my weight - but ultimately there is a steady-state weight at which the weight I reach is "optimal" for the amount of calories I am consuming. I was thinking along <a href="http://recipes.howstuffworks.com/question693.htm">these lines</a>.comment:ask.metafilter.com,2008:site.95356-1392143Sun, 29 Jun 2008 21:31:57 -0800zaebizBy: Justinian
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392170
Optimal isn't the right word; if you always eat the same amount of calories and do the same amount of exercise, there is a weight you'll naturally fall into. That weight isn't "optimal" in any sense since there is a weight you'll naturally fall into even if you eat like a pig; you'll just be fat. This natural weight increases with age as your metabolism slows.<br>
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The formula I gave is exactly what you're asking for.<br>
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Weight = (E - X - 12.7H + 6.8A - 66) / 6.23 for men.<br>
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All the variables are the ones you provided except for X, which is the number of calories you burn through exercise.comment:ask.metafilter.com,2008:site.95356-1392170Sun, 29 Jun 2008 22:15:24 -0800JustinianBy: benzo8
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392258
<a href="http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392035">chrisamiller</a>: "<i>A net gain of 3500 calories is about a pound of weight gain. (give or take a little)<br>
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So, daily weight change = (E-B)*3500</i>"<br>
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This should be: (E-B) / 3500 ...comment:ask.metafilter.com,2008:site.95356-1392258Mon, 30 Jun 2008 01:44:59 -0800benzo8By: chrisamiller
http://ask.metafilter.com/95356/How-is-a-steadystate-weight-calculated#1392411
<em>This should be: (E-B) / 3500 ...<br>
</em><br>
Yeah - thanks benzo.comment:ask.metafilter.com,2008:site.95356-1392411Mon, 30 Jun 2008 07:31:13 -0800chrisamiller