This question occurred to me while reading the current thread on the Irish Potato Famine.
I am curious what is ultimately the thing that kills most people if they are starving…lack of calories or lack of vitamins/minerals?
I think there is a distinction to be made (calories being the gas that runs the engine, vitamins are the oil…a loose analogy).
It depends on part whether or not you started with adequate vitamins and minerals on board, so to speak. Also, how active you are while starving.
Scurvy, which is the most likely deficiency, takes about six weeks to kill you (there are a bunch of variables, but let’s go with that rule of thumb). Starvation to death can happen in as little at three weeks so unless you start with scurvy or some other deficiency it’s almost certainly lack of calories that will kill you.
If you are really active during starvation - running from cave bears or what not - you’ll die faster because you’re burning calories faster. If you can carefully conserve your energy you could potentially last longer, but not much longer.
So, absent some very unusual circumstances, it will be lack of calories that kills you.
In some cases, getting too much of your calories from the wrong source (E.g a diet exclusively of lean meat with no fat or vegetation) can cause you to starve. It’s believed that Alexander Supertramp of Into the Wild fame suffered such a fate.
This was my very first experience of SD
I suspect that if you don’t eat you can hardly shit and poisons will accumulate inside you.
This is true, but is more a matter of don’t need to shit, not can’t shit:
And this is pure BS:
Once they quit eating they die in a relatively small number of days. Assuming they’d had decent nutrition up to the end of feeding, the absence of vitamins is almost certainly immaterial. It’s simply the lack of available calories.
That is a different scenario from chronic undernutrition due to widespread long-lasting food shortages.
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Or dehydration. People who have stopped eating because of the state of their health have also often stopped drinking; or at least stopped drinking anywhere near enough. Lack of water will get you long before lack of food will.
This article describes the 3 phases of starvation. It points out that an infection will likely be the cause of your demise when starving because you will have destroyed your immune system.
Rereading that column, I question this line from it:
If you were to try to live on ordinary bread, you would become hypernatremic (too much sodium in the blood–for a fine word like that you should pay me), you would vanish into a coma and in about ten days you would vanish forever out of it.
The premise of the question is you’re consuming only bread; nothing else, including water or other fluid.
I feel you wouldn’t be able to maintain this regimen while in a coma. You can’t eat and medical staff can’t feed an unconscious person bread. So once you enter a coma, you either don’t consume anything in which case you would die of lack of fluids before ten days. Or the medical staff would feed you intravenously, in which case the experiment has ended.
I kind of like this quote from that post.
I have eaten brains before, but honestly not something I might have a craving for…
That was a factor in the death of Christopher McCandless. He also mistakenly harvested a poisonous plant that looked a lot like an edible plant, and his undernourished body could not process whatever toxin that plant contained - a toxin that a well-fed person might actually have been able to handle.
Whether a person has access to clean water is also going to factor in.
So the other side of this I’ve thought about, is there any evidence that handing out multivitamins in famines or other situations where mass starvation is on the cards would actually prevent deaths at all? It seems you could ship an awful lot of them in the same volume of a small amount of food.
Which I was aware of, which is why I referred to him and the book about him in the post you’re quoting. 
Mixing them into food is probably already done in some situations.
I do know, back in my hospital days, that if a person showed up in some type of starvation (most commonly alcoholism-related, but also neglect or a pregnant woman with hyperemesis gravidarum) they would often order a “banana bag”, so called because they’re bright yellow from the riboflavin. It was usually some variation of a liter of D5NS (dextrose 5% with normal saline) and injectable multivitamins, and something extra magnesium and/or potassium if the person needed them.
One hospital I worked at had a program where they would medically stabilize alcoholics and other addicts before sending them on for detox, and for the first 3 days, they would get thiamine, folic acid, and a Centrum vitamin/mineral combo, 3 times a day, and then daily after that. One of my technicians asked me, “Why do they pack these people so full of vitamins?” and I replied, “Malnutrition, and detox is really hard on the body.”
And as for “poisons accumulating inside you”, this can definitely happen if a person is severely dehydrated.
Nope. If the problem is lack of calories then vitamins aren’t going to save anyone.
Certainly, during the re-feeding process vitamins, minerals, etc. will be very helpful but in the absence of calories they won’t do much if anything.
Ironically, I’m now getting an ad for “Intermittent Fasting For Seniors” on this page.
Though that implies its not lack of vitamins that kills you its the lack of calories.
It seems to me that the question of what kills you also depends a lot on how much body fat you started of with. An obese person suddenly deprived of food would be more likely to die of a vitamin deficiency before they ran out of fat, while a thin person might run out of fat first, and so would die of lack of calories.
And in the case of mass famines, it’s likely there was a lot of food shortages leading up to the actual famine, so people there would tend towards the thin side of the equation. I suspect fat people mostly end up in starvation scenarios due to things like shipwrecks or natural disasters, rather than famines.
Actually, no. Though the exact cause of McCandless’s death is still hotly disputed, the idea that McCandless mistook the wild sweet pea for an edible plant is one Krakauer discarded before the publication of Into the Wild. Since then, Krakauer has focused on the seeds of the wild potato, a plant McCandless’s wild plant guides described as edible. Krakauer and research scientists discovered lethal levels of a toxic amino acid, L-canavanine, in the seeds of the wild potato plant. They co-authored an article for Wilderness and Environmental Medicine, which you can read here. For an easier read, try Krakauer’s “How Chris McCandless Died”.
There’s no evidence McCandless mistook a poisonous plant for an edible one. If Krakauer, et al are correct, McCandless could not have known that a plant his guide book said was edible produces seeds containing a toxin. His emaciation would have furthered the effect. McCandless himself was convinced the seeds of the wild potato (aka the Eskimo potato) were the cause of his impending demise.
Working at the hospital, I was more than slightly surprised, and equally horrified, at how common vitamin deficiencies and protein-calorie malnutrition are in the morbidly obese.
More than once, we’d see TPN (total parenteral nutrition) ordered for someone whose gut wasn’t expected to be working for at least a week (basically, that’s the main criterion) who was morbidly obese, and the less experienced technicians would want to know why. I would tell them, “Obese people need to eat, too; they just need to eat less.”