The Straight Dope

Go Back   Straight Dope Message Board > Main > General Questions

Reply
 
Thread Tools Display Modes
  #1  
Old 05-01-2010, 02:37 PM
AClockworkMelon AClockworkMelon is offline
Guest
 
Join Date: Mar 2010
Why doesn't it take fat people longer to starve to death?

I've thought of this question before, but I was reminded of it by this thread.

1.) Fat people don't last any longer without food than normal people, do they?
2.) Why not? Don't camels survive on the fat in their humps?

Please bust my ignorance.
Reply With Quote
Advertisements  
  #2  
Old 05-01-2010, 03:05 PM
BrotherCadfael BrotherCadfael is offline
Guest
 
Join Date: Feb 2003
I've never done any research on the question, but in theory, they should indeed last longer. Why do you think they wouldn't?
Reply With Quote
  #3  
Old 05-01-2010, 03:08 PM
AClockworkMelon AClockworkMelon is offline
Guest
 
Join Date: Mar 2010
Quote:
Originally Posted by BrotherCadfael View Post
I've never done any research on the question, but in theory, they should indeed last longer. Why do you think they wouldn't?
It's just a piece of (possibly incorrect) information I've picked up.
Reply With Quote
  #4  
Old 05-01-2010, 03:22 PM
Kimstu Kimstu is offline
Guest
 
Join Date: Dec 1999
AFAIK, starvation is linked to BMI (body mass index) levels, so somebody who starts out with a higher BMI would indeed take longer to starve to death (assuming they could consume water to remain hydrated).

Heck, think about the fact that many overweight people survive for months on weight-loss diets, and lose amounts of weight that it would literally kill a thin person to lose. The fat people literally are taking longer to starve to death (although of course, the idea is to stop the slow starvation once they've got their BMI down to the desired level).
Reply With Quote
  #5  
Old 05-01-2010, 07:16 PM
Bill Door Bill Door is online now
Charter Member
 
Join Date: Nov 2003
Posts: 3,357
You have to remember that your brain needs glucose to survive. If you can't obtain it by dietary processes, either by direct ingestion of carbohydrates or by metabolism of protein, a portion of which converts to sugars, your brain will survive by converting bodily muscle tissue to glucose. It's not picky about the source of the protein, and the cardiac muscle is as available as any other muscle.

On a low calorie diet with sufficient carbohydrates or protein a fat person will live longer, but on a starvation diet, maybe not.
Reply With Quote
  #6  
Old 05-01-2010, 07:22 PM
Hari Seldon Hari Seldon is offline
Guest
 
Join Date: Mar 2002
But everyone, no matter how fat, requires water, pretty much every day.
Reply With Quote
  #7  
Old 05-01-2010, 07:23 PM
kanicbird kanicbird is offline
Guest
 
Join Date: May 1999
I think they can survive longer on a 'starvation diet' where some food it taking in, but not totally without food, as they have able the same reserves of protein and carbohydrates as anyone has, just more fat. Once the other 2 run out that's all folks.
Reply With Quote
  #8  
Old 05-01-2010, 07:57 PM
Captain Amazing Captain Amazing is online now
Member
 
Join Date: Oct 1999
Posts: 23,029
Quote:
Originally Posted by kanicbird View Post
. . .as they have able the same reserves of protein and carbohydrates as anyone has, just more fat. Once the other 2 run out that's all folks.
The body has enzymes that can convert fats to carbohydrates and vice versa, so assuming someone is otherwise healthy, they can't really run out of carbohydrates as long as they have body fat.
Reply With Quote
  #9  
Old 05-01-2010, 08:00 PM
AClockworkMelon AClockworkMelon is offline
Guest
 
Join Date: Mar 2010
So when a morbidly obese person starves to death, there won't be any fat on their corpse?
Reply With Quote
  #10  
Old 05-01-2010, 08:19 PM
Wendell Wagner Wendell Wagner is online now
Charter Member
 
Join Date: Jul 1999
Location: Greenbelt, Maryland
Posts: 11,756
According to this article, thin people do indeed starve faster than fat people:

http://en.wikipedia.org/wiki/Famine_response
Reply With Quote
  #11  
Old 05-01-2010, 09:37 PM
Simplicio Simplicio is online now
Guest
 
Join Date: Dec 2003
Quote:
Originally Posted by AClockworkMelon View Post
So when a morbidly obese person starves to death, there won't be any fat on their corpse?
I dunno. The wikipedia article kinda suggests that you'll start breaking down muscle tissue along with fats for energy once you start starving, and that the muscle loss might kill you before you deplete your fat stores. So concivable a person with little muscle and a lot of fat could still be mildly fat when starvation finally did them in.

That bit of the article isn't very well written though, so maybe not. You'd sort of think that evolution would've stumbled upon a way to hold off on eating your organs until you'd lost the beer belly.
Reply With Quote
  #12  
Old 05-01-2010, 09:57 PM
BorgHunter BorgHunter is offline
Guest
 
Join Date: Nov 2008
Quote:
Originally Posted by Simplicio View Post
That bit of the article isn't very well written though, so maybe not. You'd sort of think that evolution would've stumbled upon a way to hold off on eating your organs until you'd lost the beer belly.
This would make more sense if the concept of a beer belly was older than a couple hundred years. Natural selection can't do much about wacky theoreticals; how often would any pre-civilization (read: pre-agriculture) hominid encounter a situation in which it had such a surfeit of food that it grew to become fat, then ran out of food very suddenly?
Reply With Quote
  #13  
Old 05-01-2010, 10:00 PM
TruCelt TruCelt is offline
Member
 
Join Date: Jan 2009
Location: Near Washington, DC
Posts: 7,684
My Dad and his Airborne Ranger buds used to have a saying about what happens when people get taken prisoner (in war):

"The fat ones get skinny and the skinny ones die."

While it wasn't based on a scientific study, I can vouch for their first-hand experience in the subject.

This would probably fall in the category of "starvation diet" as opposed to the complete lack of food intake though. . .
Reply With Quote
  #14  
Old 05-02-2010, 12:55 AM
3trew 3trew is offline
Guest
 
Join Date: Jan 2003
What about the question of body composition?

I'm 5'8, 265. Multiple body fat percentage tests show that if the liposuction fairies came in the night and removed all of my body fat I'd be 5'8 and 185. If they stopped at 10%, I'd be 5'8 and 204. This clearly puts me into the fat people category, but I'm not sure where between 204 and 185 I'd become a skinny person.

I work with a guy who's my height and weighs 130. His thighs are smaller than my forearms. If the body needs to convert muscle tissue into glucose to survive, mine's got a heck of a lot more to work with.

I suspect that if he were to start packing lard onto his frame he'd be into the fat guy category well before he hit 204.
Reply With Quote
  #15  
Old 05-02-2010, 01:17 AM
AClockworkMelon AClockworkMelon is offline
Guest
 
Join Date: Mar 2010
Quote:
Originally Posted by 3trew View Post
What about the question of body composition?

I'm 5'8, 265. Multiple body fat percentage tests show that if the liposuction fairies came in the night and removed all of my body fat I'd be 5'8 and 185. If they stopped at 10%, I'd be 5'8 and 204. This clearly puts me into the fat people category, but I'm not sure where between 204 and 185 I'd become a skinny person.

I work with a guy who's my height and weighs 130. His thighs are smaller than my forearms. If the body needs to convert muscle tissue into glucose to survive, mine's got a heck of a lot more to work with.

I suspect that if he were to start packing lard onto his frame he'd be into the fat guy category well before he hit 204.
Really, 5'8 and 185 is skinny? I'm 6'0 and I weigh around 207 or so and I'm a fatass. Though I guess maybe that means I have no muscle.
Reply With Quote
  #16  
Old 05-02-2010, 01:22 AM
Shmendrik Shmendrik is offline
Guest
 
Join Date: Nov 2007
Quote:
Originally Posted by kanicbird View Post
I think they can survive longer on a 'starvation diet' where some food it taking in, but not totally without food, as they have able the same reserves of protein and carbohydrates as anyone has, just more fat. Once the other 2 run out that's all folks.
That's incorrect. There's an evolutionary reason why people get fat when they eat excess food - they're storing energy which they can burn later.
Reply With Quote
  #17  
Old 05-02-2010, 01:27 AM
AClockworkMelon AClockworkMelon is offline
Guest
 
Join Date: Mar 2010
So when people mention my weight, I can let them know that I'm stockpiling energy.
Reply With Quote
  #18  
Old 05-02-2010, 01:29 AM
3trew 3trew is offline
Guest
 
Join Date: Jan 2003
Quote:
Originally Posted by AClockworkMelon View Post
Really, 5'8 and 185 is skinny?
No, it's me with 0% body fat. It's my coworker with 50 lbs of added body fat. We're both 5'8. He'd be a fat guy long before I'd be a skinny guy, and we'd starve at different rates.
Reply With Quote
  #19  
Old 05-02-2010, 01:48 AM
Snarky_Kong Snarky_Kong is offline
Guest
 
Join Date: Oct 2004
Quote:
Originally Posted by 3trew View Post

I'm 5'8, 265. Multiple body fat percentage tests show that if the liposuction fairies came in the night and removed all of my body fat I'd be 5'8 and 185. If they stopped at 10%, I'd be 5'8 and 204. This clearly puts me into the fat people category, but I'm not sure where between 204 and 185 I'd become a skinny person.
You wouldn't be skinny. You'd be muscular. You get a big workout every day from carrying around all that extra weight.
Reply With Quote
  #20  
Old 05-02-2010, 02:21 AM
3trew 3trew is offline
Guest
 
Join Date: Jan 2003
Quote:
Originally Posted by Snarky_Kong View Post
You wouldn't be skinny. You'd be muscular. You get a big workout every day from carrying around all that extra weight.
So, I can go down to zero percent body fat, and never be skinny?
Reply With Quote
  #21  
Old 05-02-2010, 02:32 AM
vinylmatt vinylmatt is offline
Guest
 
Join Date: May 2010
Quote:
Originally Posted by 3trew View Post
So, I can go down to zero percent body fat, and never be skinny?
I don't think zero body fat is something anyone gets to. I saw a documentary a few years ago about a body builder for those posing shows. He would get to 2-3% fat coming up to a show by pretty much only eating tins of tuna, and he looked creepy.
Reply With Quote
  #22  
Old 05-02-2010, 02:43 AM
jackdavinci jackdavinci is offline
Guest
 
Join Date: Apr 2000
WAG but, while a fat person may take longer to starve, they don't have any extra water stored in their body so they will die of thirst long long before they starve to death.
Reply With Quote
  #23  
Old 05-02-2010, 07:05 AM
Bill Door Bill Door is online now
Charter Member
 
Join Date: Nov 2003
Posts: 3,357
Quote:
Originally Posted by Captain Amazing View Post
The body has enzymes that can convert fats to carbohydrates and vice versa, so assuming someone is otherwise healthy, they can't really run out of carbohydrates as long as they have body fat.

I don't think gluconeogenesis works on fats. You can metabolize fat to ketones and use ketones for energy, but the brain demands glucose. On an all fat diet you'll constantly be losing muscle mass as you convert muscle to glucose to survive.
Reply With Quote
  #24  
Old 05-02-2010, 07:10 AM
Chief Pedant Chief Pedant is offline
Guest
 
Join Date: Feb 2007
Quote:
Originally Posted by Captain Amazing View Post
The body has enzymes that can convert fats to carbohydrates and vice versa, so assuming someone is otherwise healthy, they can't really run out of carbohydrates as long as they have body fat.
Without sidetracking the thread too much into a discussion of metabolism, I don't think it is correct to imply that fats are substrates for gluconeogenesis in humans.

In short, for the most part carbohydrates to fats is an unfortunate one-way street in people. From an energy standpoint, this is an issue mostly for the brain, which really really likes glucose for its energy substrate.

To the OP:
A person with significant fat stores would last longer, on average, than a person without them. There are other factors at play. An ideal candidate would be a fairly healthy fat guy with plenty of muscle.

On review: What Bill said.

Last edited by Chief Pedant; 05-02-2010 at 07:14 AM..
Reply With Quote
  #25  
Old 05-02-2010, 07:38 AM
Lumpy Lumpy is offline
Charter Member
 
Join Date: Aug 1999
Location: Minneapolis, Minnesota US
Posts: 12,337
Quote:
Originally Posted by BorgHunter View Post
This would make more sense if the concept of a beer belly was older than a couple hundred years. Natural selection can't do much about wacky theoreticals; how often would any pre-civilization (read: pre-agriculture) hominid encounter a situation in which it had such a surfeit of food that it grew to become fat, then ran out of food very suddenly?
It's older than a couple of hundred years; the word "paunch" has medieval origins going back to Latin. As long as people have had access to carb-rich diets (and especially alcohol), they've had the human equivalent of camel humps.
Reply With Quote
  #26  
Old 05-02-2010, 07:39 AM
Bijou Drains Bijou Drains is offline
Guest
 
Join Date: Sep 2008
How many people starve to death in Western countries? There is one famous case , Chris McCandeless of Into The Wild.
Reply With Quote
  #27  
Old 05-02-2010, 01:21 PM
rhubarbarin rhubarbarin is offline
Guest
 
Join Date: Aug 2009
I've never read anything to indicate that larger people (whether or not their mass is fat or muscle) don't survive longer in general when it comes to starvation or harsh conditions. This is probably the reason research has showed that 'overweight' people live longer, on average, than those in the 'ideal' BMI range - if they have the misfortune to become terminally ill or injured, they have an advantage in having more bodily stores.

Keep in mind that death from starvation and malnutrition are not the same. Fat people could easily die from various forms of malnutrition and deficiences while still maintaning high body fat.

However, excess body fat is a disorder of the metabolism, nothing to do with storing surplus energy for famine. Species do not become fat when there is a food surplus (although they become fat for other reasons governed by hormonal balance, such as hibernation), they multiply. Unless the food they are eating promotes the metabolic changes that lead to obesity, as is the problem with our unnatural (in terms of the human animal for the majority of our evolution) modern diet, and was a persistant problem with zoo animals (leading to the common modern human problems such as obesity, heart disease, diabetes, and infertility) until an effort was made to provide each with a diet that closely mimics what they eat in their natural habitat.

I have a BMI of 16 with a normal body fat percentage (19%). Obviously I would be 'fat', not in terms of BMI but in body fat percentage, at a much lower total poundage than the vast majority of people. I am sure I would die much more quickly in the absence of food than average size or large people, as well, since I have so little total soft tissue to live off of, as well as having a very high requirement for daily calories to maintain my current weight (2200 to 3200 daily, and I'm only moderately active).

Last edited by rhubarbarin; 05-02-2010 at 01:21 PM..
Reply With Quote
  #28  
Old 05-02-2010, 01:50 PM
Superfluous Parentheses Superfluous Parentheses is offline
Guest
 
Join Date: Dec 2007
Quote:
Originally Posted by Bijou Drains View Post
How many people starve to death in Western countries? There is one famous case , Chris McCandeless of Into The Wild.
Right now? I dunno. Not many. A century and a half ago, plenty. Half a century ago, still quite a few.

Last edited by Superfluous Parentheses; 05-02-2010 at 01:51 PM..
Reply With Quote
  #29  
Old 05-02-2010, 02:32 PM
Wendell Wagner Wendell Wagner is online now
Charter Member
 
Join Date: Jul 1999
Location: Greenbelt, Maryland
Posts: 11,756
Actually, rubarbarbin, it's not true that fat people live longer on average than thinner people. Thinner people live longer, although it's not a large difference. It's only a few months longer lifespan on average.

The reason is that there are advantages going both ways. Carrying around extra weight is not good for the heart, so most of the advantage there is to thinner people. For some other causes of death though, there is some advantage to being heavier. On balance, it's better not to be overweight.
Reply With Quote
  #30  
Old 05-02-2010, 02:36 PM
Rigamarole Rigamarole is offline
Guest
 
Join Date: Dec 2005
When David Blaine did his little starvation-in-a-glass-box stunt, he fattened himself up considerably before beginning. It seemed to help.
Reply With Quote
  #31  
Old 05-02-2010, 02:37 PM
Simplicio Simplicio is online now
Guest
 
Join Date: Dec 2003
Quote:
Originally Posted by Bijou Drains View Post
How many people starve to death in Western countries? There is one famous case , Chris McCandeless of Into The Wild.
Aren't a lot of people in vegetative states eventually 'let go' by having their feeding tube removed?
Reply With Quote
  #32  
Old 05-02-2010, 03:25 PM
TruCelt TruCelt is offline
Member
 
Join Date: Jan 2009
Location: Near Washington, DC
Posts: 7,684
New Scientist has an aside about it this week. They said that the limiting factor is actually the amount of available b vitamins. On a water and and vitamin diet, you could live 'til the body fat runs out. But without b vitamins, the body fat can't be converted.
Reply With Quote
  #33  
Old 05-02-2010, 03:35 PM
Bryan Ekers Bryan Ekers is online now
Guest
 
Join Date: Nov 2000
So has that fat guy on Lost shed any weight yet? Or did they find the inter-dimensional Krispy Kreme in the island's wormhole?
Reply With Quote
  #34  
Old 05-02-2010, 03:48 PM
astro astro is offline
Guest
 
Join Date: Jul 1999
Quote:
Originally Posted by AClockworkMelon View Post
So when a morbidly obese person starves to death, there won't be any fat on their corpse?
With just water and literally zero food the physical stress of pure starvation can easily kill a significantly obese person well before all fat stores are completely used up. If you have some minor amount of food it's easier to glide down to near zero fat like concentration camp survivors.
Reply With Quote
  #35  
Old 05-02-2010, 05:38 PM
kanicbird kanicbird is offline
Guest
 
Join Date: May 1999
Quote:
Originally Posted by Captain Amazing View Post
The body has enzymes that can convert fats to carbohydrates and vice versa, so assuming someone is otherwise healthy, they can't really run out of carbohydrates as long as they have body fat.
Yes but that requires protein, which is not stored like fat and is a limit as to how much stored fat one can use before dieing.

So it is needed to consume some carbs and or protein to preserve protein.
Reply With Quote
  #36  
Old 05-02-2010, 05:41 PM
kanicbird kanicbird is offline
Guest
 
Join Date: May 1999
Quote:
Originally Posted by Shmendrik View Post
That's incorrect. There's an evolutionary reason why people get fat when they eat excess food - they're storing energy which they can burn later.
See above, protein is required to manufacture carbs from fat, eating nothing means the body will cannibalize itself to get enough carbs, so a fat person will not survive longer. But if there is some food such as insects, then the person should have enough dietary protein to prevent cannibalization - which is a advantage for a fat person.
Reply With Quote
  #37  
Old 05-02-2010, 05:50 PM
PatriotGrrrl PatriotGrrrl is offline
Guest
 
Join Date: Jun 2005
Nope, the body can make carbs from protein (called gluconeogenesis) - not from fat.
Reply With Quote
  #38  
Old 05-03-2010, 12:07 PM
rhubarbarin rhubarbarin is offline
Guest
 
Join Date: Aug 2009
Quote:
Originally Posted by Wendell Wagner View Post
Actually, rubarbarbin, it's not true that fat people live longer on average than thinner people. Thinner people live longer, although it's not a large difference. It's only a few months longer lifespan on average.

The reason is that there are advantages going both ways. Carrying around extra weight is not good for the heart, so most of the advantage there is to thinner people. For some other causes of death though, there is some advantage to being heavier. On balance, it's better not to be overweight.

Cite?
Reply With Quote
  #39  
Old 05-03-2010, 08:04 PM
Wendell Wagner Wendell Wagner is online now
Charter Member
 
Join Date: Jul 1999
Location: Greenbelt, Maryland
Posts: 11,756
rubarbarbin, here's the best citation I've been able to find with a quick search:

http://www.usatoday.com/news/health/...lifespan_N.htm

Being overweight by less than 30 pounds reduces lifespan on average by a few months. Being overweight by 30 pounds or somewhat more reduces lifespan on average by about a year. Being overweight by 80 pounds or so reduces lifespan average by at least three years. The more you're overweight by more than 80 pounds, the shorter the average lifespan you can expect.

Could someone who's a doctor give us a better citation?
Reply With Quote
  #40  
Old 05-03-2010, 10:18 PM
Lumpy Lumpy is offline
Charter Member
 
Join Date: Aug 1999
Location: Minneapolis, Minnesota US
Posts: 12,337
I've sometimes thought that if I ever met a genetically-engineered supersoldier who sneeringly asked me what my genes were good for, I could reply "surviving recurrent periods of famine".
Reply With Quote
  #41  
Old 05-03-2010, 10:24 PM
AClockworkMelon AClockworkMelon is offline
Guest
 
Join Date: Mar 2010
Well it seems like I'm getting mixed responses.

Does it take longer for fat people to starve to death?
__________________
"You're a veritable wise man when it comes to human relations, AClockworkMelon." Freudian Slit
Reply With Quote
  #42  
Old 05-03-2010, 11:18 PM
Kimstu Kimstu is offline
Guest
 
Join Date: Dec 1999
Yes it does, as long as they can drink water. As noted by other posters, being fat doesn't provide any protection against dying of thirst.

Moreover, you can't assume that, say, having a BMI twice as high as another person means you'd take twice as long to starve to death. Fat reserves do provide important energy resources for survival when calories are scarce (that's why we evolved the ability to accumulate fat reserves, after all), but AFAIK there's no simple equation along the lines of X pounds of extra fat will allow you to go Y extra days without food.
Reply With Quote
  #43  
Old 05-04-2010, 06:52 PM
AClockworkMelon AClockworkMelon is offline
Guest
 
Join Date: Mar 2010
Our fat reserves can't help with thirst at all? Isn't that how camels do it?

And yes, I know we're not camels and appreciate that camels might have processes we don't. Just curious if that's it or not.
Reply With Quote
  #44  
Old 05-04-2010, 06:55 PM
Shmendrik Shmendrik is offline
Guest
 
Join Date: Nov 2007
Quote:
Originally Posted by kanicbird View Post
See above, protein is required to manufacture carbs from fat, eating nothing means the body will cannibalize itself to get enough carbs, so a fat person will not survive longer. But if there is some food such as insects, then the person should have enough dietary protein to prevent cannibalization - which is a advantage for a fat person.
Cite? My biochemistry textbook disagrees with you.
Reply With Quote
  #45  
Old 05-04-2010, 11:28 PM
Chickie Chickie is offline
Guest
 
Join Date: Mar 2010
According to Wikipedia, the position of a camel's fatty tissue in the hump minimizes the amount of heat that a more generally-spread subcutaneous layer of fat would trap in the body, thus keeping the animal cooler. This among other adaptations like blood-cell shape and better conservation of liquid in the respiration and digestive processes.

Last edited by Chickie; 05-04-2010 at 11:28 PM..
Reply With Quote
  #46  
Old 05-05-2010, 05:59 PM
astro astro is offline
Guest
 
Join Date: Jul 1999
Quote:
Originally Posted by AClockworkMelon View Post
Well it seems like I'm getting mixed responses.

Does it take longer for fat people to starve to death?
I think your question was answered several times.

Answer: "Yes" it takes a fat person longer to starve to death, but fat does not provide everything the body needs metabolically, and starvation puts huge stresses on the body, so a fat person that has nothing at all to eat will last longer than a less fat person, but will likely die well before all their fat reserves are completely used up.
Reply With Quote
  #47  
Old 05-05-2010, 06:10 PM
AClockworkMelon AClockworkMelon is offline
Guest
 
Join Date: Mar 2010
Quote:
Originally Posted by astro View Post
I think your question was answered several times.

Answer: "Yes" it takes a fat person longer to starve to death, but fat does not provide everything the body needs metabolically, and starvation puts huge stresses on the body, so a fat person that has nothing at all to eat will last longer than a less fat person, but will likely die well before all their fat reserves are completely used up.
Yes, my question was answered several times.

Quote:
Originally Posted by kanicbird View Post
a fat person will not survive longer
Thus the "mixed responses" I mentioned.

Thanks for the answers from everyone.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 08:34 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@chicagoreader.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Publishers - interested in subscribing to the Straight Dope?
Write to: sdsubscriptions@chicagoreader.com.

Copyright 2013 Sun-Times Media, LLC.