Reply
 
Thread Tools Display Modes
  #1  
Old 06-11-2003, 05:28 PM
relliksmom relliksmom is offline
Guest
 
Join Date: Jun 2003
Location: Santa Cruz, CA
Posts: 1
Could a lactating woman survive on her own breast milk?

While enjoying the dreamy state I entered while nursing my 8 month old son the other day, I pondered: If a lactating woman was stranded without food (but sufficient supplies of water), how long could she survive on her own breast milk? (I'm making the assumption the mother was stranded without her child). Further, could she support another adult?
  #2  
Old 06-11-2003, 05:43 PM
Mangetout's Avatar
Mangetout Mangetout is offline
Member
 
Join Date: May 2001
Location: England
Posts: 57,839
No; she would die more quickly because energy is lost in the digestion process and in converting the stuff back to milk in her breasts.
  #3  
Old 06-11-2003, 05:48 PM
Blake Blake is offline
Member
 
Join Date: Mar 2001
Posts: 11,049
No and not really.
Producing milk is very energy expensive. This energy has to come form somewhere. In the absence of food the only place for it to come from is the bodyís own fat reserves. And of course milk I matter, and the matter also has t come from somewhere. Again, this is provided by the body, mostly by stripping fat.

The trouble is that itís not very efficient. Normally when using reserves you are converting fat into food, with a moderate loss of energy. In this scenario you are talking about converting fat into food, with a moderate loss of energy, and then converting that food into milk, with an even greater loss of energy. Youíd starve to death far faster than if you simply used the fat reserves directly.

To make matters worse the body doesnít know why you are trying to produce milk. It assume sit is to feed a child, and it continues to add protein to the mix. Trouble is the body doesnít add protein, so it starts stripping your muscles to provide it. This is not good.

Milk doesnít actually produce anything It just takes whatís already available and converts it into another form, losing energy in the process.

Supporting an adult in the short term would be possible. It assumes that the woman has large fat reserves and the other person has none at all. But it would be possible to provide enough food to prolong that personís life somewhat. She would essentially be feeding them her fat reserves.
  #4  
Old 06-11-2003, 05:54 PM
malkavia malkavia is offline
Guest
 
Join Date: Nov 2000
Location: Phoenix
Posts: 2,215
Quote:
Supporting an adult in the short term would be possible. It assumes that the woman has large fat reserves and the other person has none at all. But it would be possible to provide enough food to prolong that personís life somewhat. She would essentially be feeding them her fat reserves.
Say hello to the fad diet of the future.
  #5  
Old 06-11-2003, 06:04 PM
handy handy is offline
BANNED
 
Join Date: Mar 1999
Location: Pacific Grove, Calif
Posts: 17,493
You'd need a biochemist. I tried for years to figure out how long a person could go just on their own body fluids & fingernails & stuff & never got an answer. There are too many variables.

In school they taught us that there is only a 10 percent energy transfer from food. Like if you had 10lbs of milk, you could only get 1lb of energy from it. But I dunno if thats the same anymore.
  #6  
Old 06-11-2003, 06:38 PM
MsWhatsit MsWhatsit is offline
Charter Member
 
Join Date: Jul 2000
Location: Columbus, OH
Posts: 12,267
This is a side issue to the OP's question, but I would further point out that in a desert island scenario, it would be very difficult for the woman to express enough milk to be able to subsist on, even assuming that producing milk wouldn't strip her fat reserves (which, of course, in reality it would). Absent the presence of an actual baby, your body doesn't produce the hormones that stimulate the let-down reflex; besides which, hand-expressing is pretty difficult and I'm guessing you don't have your state of the art electric breastpump on the desert island.
  #7  
Old 06-11-2003, 06:55 PM
Keeve Keeve is offline
Guest
 
Join Date: Aug 2000
Location: NY/NJ, USA
Posts: 5,079
Sure sounds like a perpetual-motion machine to me....
  #8  
Old 06-11-2003, 07:14 PM
Blake Blake is offline
Member
 
Join Date: Mar 2001
Posts: 11,049
Quote:
Like if you had 10lbs of milk, you could only get 1lb of energy from it.

What is a pound of energy? The only relationship I know between energy and mass is E = MC^2. If thatís the pound of energy they mean then a human could live his entire life on a 10 pounds of milk.

I think perhaps you are referring to the efficiency of the body? As in only 10% of the chemical energy in food is recovered, the rest being lost as heat etc.
  #9  
Old 06-11-2003, 07:33 PM
Shade Shade is offline
Guest
 
Join Date: Oct 2001
Location: Cambridge. No, the UK one
Posts: 4,272
As a rule of thumb, if you draw a big box round a system, and less energy goes in than comes out, it's screwed.

I don't know how long a woman could survive, but it can hardly be better (maybe a bit for some obscure reason) than just sitting there conserving the energy.
  #10  
Old 06-11-2003, 07:35 PM
Exapno Mapcase Exapno Mapcase is online now
Charter Member
 
Join Date: Mar 2002
Location: NY but not NYC
Posts: 30,848
Recent previous thread on this question:
http://boards.straightdope.com/sdmb/...hreadid=177167
  #11  
Old 06-11-2003, 07:38 PM
Padeye Padeye is offline
Member
 
Join Date: Nov 1999
Location: Phoenix, AZ, US
Posts: 7,672
Repeat after me, "The Matrix violates the second law of thermodynamics."
  #12  
Old 06-11-2003, 08:24 PM
Achernar Achernar is offline
Guest
 
Join Date: Aug 1999
Location: 23 male, Boston
Posts: 5,791
It's not a matter of Thermodynamics! The woman isn't a closed system; the OP said she had water, at least. As it turns out, that's not enough, but not because of freaking conservation of energy.
  #13  
Old 06-11-2003, 08:33 PM
Blake Blake is offline
Member
 
Join Date: Mar 2001
Posts: 11,049
It is kind of. Food (including milk) is a source of energy. Water is not. If the woman could survive on her own milk then there would need to be, at the very least, no energy lost within the system.
  #14  
Old 06-11-2003, 08:41 PM
Achernar Achernar is offline
Guest
 
Join Date: Aug 1999
Location: 23 male, Boston
Posts: 5,791
It's a similar concept, but it's not the one the Second Law of Thermodynamics addresses. You could also say a man can't make enough money to live off by giving himself cash gifts, but good luck proving that with dQ <= TdS.
  #15  
Old 06-11-2003, 08:47 PM
Rabid_Squirrel Rabid_Squirrel is offline
Guest
 
Join Date: Feb 2003
Location: En Zed
Posts: 1,428
Yeap, Shade's got it in a nutshell.

- Is the woman producing mass or energy out of thin air?
- Is anything leaving the woman?
- Is there anything entering the woman?
- Does the flow in = flow out?

The woman would be losing water through breathing/urine/feaces, and carbon via exhaled air, as well as a number of vitamins/minerals. Also, energy is lost unless the woman sits in a room at body temperature and does not respirate (ie, dead).
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 06:29 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@straightdope.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.)

Copyright © 2018 STM Reader, LLC.

 
Copyright © 2017