# Living off body fat without eating? **URL:** \ **Category:** Factual Questions\ **Created:** [January 29, 2009, 11:35pm UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636 "2009-01-29T23:35:22Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Busy\_Scissors](https://avatars.discourse-cdn.com/v4/letter/b/d78d45/32.png) [@Busy\_Scissors](https://boards.straightdope.com/u/Busy_Scissors)\ **Post date:** [January 29, 2009, 11:35pm UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/1 "2009-01-29T23:35:22Z")
There was a horizon program on BBC2 this week called ‘Why are thin people not fat?’ [Link here for purposes of thread](http://www.bbc.co.uk/iplayer/episode/b00hbsk2/Horizon_Why_Are_Thin_People_Not_Fat/) It was OK. Basic premise was to take a bunch of skinny people and get them to binge eat for a few weeks and record the results. One claim was made that raised an eyebrow with me. At 10 min 20 secs on the link, the narrator describes a Scottish PhD student conducting an experiment with a 450 lb man in 1968. Without eating _anything_, just drinking water and taking vitamins for 1 year and 2 weeks, the guy lost 275lbs in weight. Now Horizon is a popular science program, so some corners are going to be cut in terms of rigour. Still, the program has a wide audience so I wouldn’t expect to hear completely outlandish claims. No food for 54 weeks though? Surely not possible - what say you? ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [January 29, 2009, 11:46pm UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/2 "2009-01-29T23:46:43Z")
> [@Busy\_Scissors](#): > > [Link here for purposes of thread](http://www.bbc.co.uk/iplayer/episode/b00hbsk2/Horizon_Why_Are_Thin_People_Not_Fat/) Apparently, only people living in the UK can watch it. ---
**Author:** ![YamatoTwinkie](https://avatars.discourse-cdn.com/v4/letter/y/cc9497/32.png) [@YamatoTwinkie](https://boards.straightdope.com/u/YamatoTwinkie)\ **Post date:** [January 29, 2009, 11:48pm UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/3 "2009-01-29T23:48:07Z")
you figure ~3500 calories per pound of fat, and your average skinny person needs to eat ~1600 cal/day at a minimum to maintain weight. So 275lbs\*3500/1600= 601 days of storage. I _guess_ its possible, assuming he got enough other nutrients to ward off malnutrition. I can’t imagine it’s healthy. ---
**Author:** ![erislover](https://avatars.discourse-cdn.com/v4/letter/e/71e660/32.png) [@erislover](https://boards.straightdope.com/u/erislover)\ **Post date:** [January 29, 2009, 11:50pm UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/4 "2009-01-29T23:50:28Z")
275 pounds is about 124738 grams. At 9 Calories per gram of fat, that’s 1 122 642 Calories. Picking a round number, no pun intended, let’s say our male requires 2000 Calories a day. At 2000 Calories per day x 7 days per week x 54 weeks that’s 756,000 Calories. So, it is plausible for that particular reason. ---
**Author:** ![Busy\_Scissors](https://avatars.discourse-cdn.com/v4/letter/b/d78d45/32.png) [@Busy\_Scissors](https://boards.straightdope.com/u/Busy_Scissors)\ **Post date:** [January 29, 2009, 11:54pm UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/5 "2009-01-29T23:54:26Z")
> [@clairobscur](#): > > Apparently, only people living in the UK can watch it. Sorry, didn’t realise it was UK only access. In any case, the statement made on the program is as I typed. I’m sure the guy must have been out for a cheeky wee pie and chips on the quiet. ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [January 29, 2009, 11:55pm UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/6 "2009-01-29T23:55:27Z")
\*\*9 calories/gram \*\*and **3,500/pound**. Does it work that way? Or is there some kind of cost to get the fat out of storage and converted into energy? And if you starved for a year, what issues would you have when you start eating again? ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [January 30, 2009, 12:14am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/7 "2009-01-30T00:14:53Z")
[This article from 1972 may be related.](http://boards.straightdope.com/sdmb/showthread.php?t=504227) The authors cite an earlier study (apparently authored by themselves) on “controlled starvation” in 27 patients, of which the largest weight loss was 275 lb. Unfortunately, only the first page appears to be available for free, so I don’t have access to the citation for the earlier article. ---
**Author:** ![Capcha](https://avatars.discourse-cdn.com/v4/letter/c/82dd89/32.png) [@Capcha](https://boards.straightdope.com/u/Capcha)\ **Post date:** [January 30, 2009, 1:58am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/8 "2009-01-30T01:58:39Z")
i would think that the digestive system (stomach and guts) suffer damage from lack of [use](http://www.eatingproblems.org/epseffect.html). > [@](#): > > **Effects of Anorexia Nervosa** > > Starvation: Starvation can have very serious effects on all major body systems and organs. The basic metabolic response to starvation is to conserve body tissues and energy. However, the body will also start to use its own tissue, including muscle and organs, for energy since the body has no food to use instead, The liver and intestines > typically lose the highest percentage of their own weight during starvation, followed by the heart and kidneys which both lose a moderate amount of weight. This often causes permanent damage to the organs in the process. Because someone’s heart size may be reduced, they will experience low blood pressure and a slowed pulse. It cans also lead to cardiac arrest or kidney failure. Total starvation is usually fatal in 8 to 12 weeks. It’s not the regimen mentioned in the OP, but it comes close i think. ---
**Author:** ![HMS\_Irruncible](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hms_irruncible/32/7394_2.png) [@HMS\_Irruncible](https://boards.straightdope.com/u/HMS_Irruncible)\ **Post date:** [January 30, 2009, 2:38am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/9 "2009-01-30T02:38:30Z")
> [@Busy\_Scissors](#): > > There was a horizon program on BBC2 this week called ‘Why are thin people not fat?’ > > [Link here for purposes of thread](http://www.bbc.co.uk/iplayer/episode/b00hbsk2/Horizon_Why_Are_Thin_People_Not_Fat/) > > It was OK. Basic premise was to take a bunch of skinny people and get them to binge eat for a few weeks and record the results. One claim was made that raised an eyebrow with me. At 10 min 20 secs on the link, the narrator describes a Scottish PhD student conducting an experiment with a 450 lb man in 1968. Without eating _anything_, just drinking water and taking vitamins for 1 year and 2 weeks, the guy lost 275lbs in weight. > > Now Horizon is a popular science program, so some corners are going to be cut in terms of rigour. Still, the program has a wide audience so I wouldn’t expect to hear completely outlandish claims. No food for 54 weeks though? Surely not possible - what say you? The human body requires glucose to operate, and cannot manufacture it from body fat. It can be recovered by breaking down muscle however. If someone went without food for 54 weeks, that means they lost a hell of a lot of muscle (including cardiac muscle as well). This is a grossly irresponsible thing to do; that man could easily have died. The liability alone makes it suspect to me, and how did they actually get a man not to eat anything for a year? I would think one would have to be physically restrained 24x7. ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [January 30, 2009, 3:17am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/10 "2009-01-30T03:17:27Z")
> [@](#): > > Total starvation is usually fatal in 8 to 12 weeks. Does this mean that the 333 rule only means “without permanent damage”? That is, three minutes without oxygen, three days without water, or three weeks without food. ---
**Author:** ![John\_H\_1](https://avatars.discourse-cdn.com/v4/letter/j/e9bcb4/32.png) [@John\_H\_1](https://boards.straightdope.com/u/John_H_1)\ **Post date:** [January 30, 2009, 4:20am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/11 "2009-01-30T04:20:30Z")
The wikipedia article on fat implies that it is turned into into glucose by the body. Am I missing something? “Fats are broken down in the body to release glycerol and free fatty acids. The glycerol can be converted to glucose by the liver and thus used as a source of energy.” ---
**Author:** ![SciFiSam](https://avatars.discourse-cdn.com/v4/letter/s/47e85d/32.png) [@SciFiSam](https://boards.straightdope.com/u/SciFiSam)\ **Post date:** [January 30, 2009, 4:30am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/12 "2009-01-30T04:30:49Z")
> [@John\_H\_1](#): > > The wikipedia article on fat implies that it is turned into into glucose by the body. Am I missing something? > > “Fats are broken down in the body to release glycerol and free fatty acids. The glycerol can be converted to glucose by the liver and thus used as a source of energy.” Yup - that’s ketosis. Ketoacidosis is what arises when the liver’s been doing that for too long. It can kill. If someone really went without food altogether for over a year, their prognosis would not be good. I’m finding it hard to get links for this; I read about it a long time ago, but everything I can find online now is about diabetic or alcoholic ketosis and how to treat it - nothing about how it actually can cause someone to die. ---
**Author:** ![Maastricht](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@Maastricht](https://boards.straightdope.com/u/Maastricht)\ **Post date:** [January 30, 2009, 4:42am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/13 "2009-01-30T04:42:02Z")
Heavy people have more body to maintain, so they would need more then your basic 2000 calories a day. That might change the calculation? ---
**Author:** ![Rigamarole](https://avatars.discourse-cdn.com/v4/letter/r/77aa72/32.png) [@Rigamarole](https://boards.straightdope.com/u/Rigamarole)\ **Post date:** [January 30, 2009, 5:32am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/14 "2009-01-30T05:32:30Z")
> [@Maastricht](#): > > Heavy people have more body to maintain, so they would need more then your basic 2000 calories a day. That might change the calculation? Quite a lot more. Most calculators claim I need 2800-3000 calories a day as a moderately active adult male and I only weigh 180 pounds. The whole 2000 calorie/day “average” is a load of manure. Maybe for tiny women 2000 calories or even a little less works, but 2000 is pretty low-end for most people. Hell your average meal at a restaurant these days is something like 1200+ calories. ---
**Author:** ![outlierrn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/outlierrn/32/3005_2.png) [@outlierrn](https://boards.straightdope.com/u/outlierrn)\ **Post date:** [January 30, 2009, 6:09am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/15 "2009-01-30T06:09:13Z")
no protein, no carbohydrates and no essential fatty acids (you don’t store those)? With only 1968 understanding of vitamin, mineral and micronutrient needs? I call a loud and hardy bullshit ---
**Author:** ![Busy\_Scissors](https://avatars.discourse-cdn.com/v4/letter/b/d78d45/32.png) [@Busy\_Scissors](https://boards.straightdope.com/u/Busy_Scissors)\ **Post date:** [January 30, 2009, 8:05am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/16 "2009-01-30T08:05:59Z")
> [@bibliophage](#): > > [This article from 1972 may be related.](http://boards.straightdope.com/sdmb/showthread.php?t=504227) The authors cite an earlier study (apparently authored by themselves) on “controlled starvation” in 27 patients, of which the largest weight loss was 275 lb. Unfortunately, only the first page appears to be available for free, so I don’t have access to the citation for the earlier article. Your link doesn’t work for me **Bibliophage** - it just links to this thread. Would you mind re-posting a link to the article? Thanks. ---
**Author:** ![si\_blakely](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@si\_blakely](https://boards.straightdope.com/u/si_blakely)\ **Post date:** [January 30, 2009, 8:23am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/17 "2009-01-30T08:23:14Z")
> [@Capcha](#): > > It’s not the regimen mentioned in the OP, but it comes close i think. Not really. People in the end stages of Anorexia have no body fat remaining to draw energy from, so their body starts drawing on muscle tissue - leading to organ degradation. In the case mentioned in the documentary, the subject dropped from 450lb to 175lb - he would have had some remaining body fat at the end, and thus never dropped into the muscle/organ breakdown zone. And he was not starving in isolation - he was being monitored by a medical student doing a PhD who was supervised by a medical professional. So it is unlikely that at any stage the subjects health was at substantial risk - they would have cut the experiment short (even in 1968 there were ethics committees in charge of such things). Given appropriate medical monitoring and suitable nutrients, I see no reason why someone of that weight could not go without food for a year. How the subject dealt with the whole “not actually eating” thing would make an interesting psychological study. _“Tell me. And remember, this is for posterity so be honest. How do you feel?”_ Si ---
**Author:** ![Hostile\_Dialect](https://avatars.discourse-cdn.com/v4/letter/h/e495f1/32.png) [@Hostile\_Dialect](https://boards.straightdope.com/u/Hostile_Dialect)\ **Post date:** [January 30, 2009, 8:29am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/18 "2009-01-30T08:29:08Z")
> [@Busy Scissors](#): > > Now Horizon is a popular science program, so some corners are going to be cut in terms of rigour. Still, the program has a wide audience so I wouldn’t expect to hear completely outlandish claims. [Never, ever, _ever_ trust the BBC on science, just to be safe.](http://languagelog.ldc.upenn.edu/nll/?p=334) ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [January 30, 2009, 10:25am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/19 "2009-01-30T10:25:10Z")
> [@Busy\_Scissors](#): > > Your link doesn’t work for me **Bibliophage** - it just links to this thread. Would you mind re-posting a link to the article? Thanks. Sorry. Try [this](http://scholar.google.com/scholar?hl=en&lr=&q=info:2iKpR-xDsoYJ:scholar.google.com/&output=viewport&pg=1) instead. ---
**Author:** ![Toxylon](https://avatars.discourse-cdn.com/v4/letter/t/f05b48/32.png) [@Toxylon](https://boards.straightdope.com/u/Toxylon)\ **Post date:** [January 30, 2009, 11:54am UTC](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636/20 "2009-01-30T11:54:13Z")
> [@Santo\_Rugger](#): > > Does this mean that the 333 rule only means “without permanent damage”? That is, three minutes without oxygen, three days without water, or three weeks without food. The 333 rule is a gross oversimplification: the time required to die or even be permanently disabled from any of the causes depends on a multitude of factors. People have recovered from way longer than 3 minutes without oxygen, way more than three days without water and way more than three weeks without food, yet, given appropriate circumstances, a person could perish from dehydration or starvation quite a bit faster than the ‘333’ implies (I guess oxygen deprivation has a similar spectrum). Stay at 70 degrees F, exert little energy, have lots of water at hand, and three weeks without food will not kill you. Go running around at 100 degrees F, snacking on beef jerky, and it won’t take 72 h to die from dehydration. [Next page](https://boards.straightdope.com/t/living-off-body-fat-without-eating/483636.md?page=2)