I hope that this question qualifies for worldbuilding. Take my apologies if it's too specific / not specific enough.

In a post-apocalyptic desert-like environment with only a few million people left worldwide, for hundreds of miles, one warlord has a monopoly of growing food. Water is rare yet available, but plants are not.

Our warlord wants to trade food (i.e. nutrition) for gasoline, but paranoidly wants to ensure that not even a single live grain/seedling/egg/whatever will ever leave his farms and jeopardize his monopoly. Nothing that he sells may be able to reproduce/grow.

Hence he withdraws blood from his underlings, and literally trades blood for oil.

  1. What single source of food is hardest to keep from reproduction while still being nutritious? (I need something resilient to point at and say "hey, since that´s all they have left, it absolutely makes sense to save my blood-for-oil-joke")
  2. Is there a reason while human blood (700kcal/liter) would be unsuited as nutrition in a life-or-death situation?
  • 1
    $\begingroup$ You might be interested in Could a humanesque creature derive all its nutrients from drinking blood?. In particular, while not a great answer to that question, this answer points to one potential problem with relying on blood for nutrition. Also, How much blood does a vampire need? deals with the energy requirements and how this translates to amounts of blood. $\endgroup$
    – user
    Oct 10, 2015 at 23:02
  • $\begingroup$ Which technology level? Anything lower than the 80s, you are sure just by tranding dead animals / seedless fruits / flours (for cereals/potatoes). As for blood, it can be used as a last resource but a) in uneconomical and b) is a gigantic health risk. $\endgroup$
    – SJuan76
    Oct 10, 2015 at 23:15
  • $\begingroup$ Doesn't Mad Max: Fury Road have some kind of post-apocalyptic blood trade? I've never seen it, but that's what I gather. $\endgroup$
    – zeta
    Oct 11, 2015 at 2:11
  • $\begingroup$ Sell the food cooked and or mashed (puree, flour, dried and powdered...). Nothing can grow from that. $\endgroup$
    – Davidmh
    Oct 24, 2015 at 21:25
  • $\begingroup$ What about selling already cooked products ? Boiled grains can't germinate. $\endgroup$
    – Petit Lama
    Oct 25, 2015 at 15:07

3 Answers 3


I can do no better than quote Charles Stross's "The Rhesus Chart":

Human blood is a poor nutrient source; it's about 60 per cent plasma by volume and only provides about 900 calories per liter, so your hypothetical blood-sucking fiend is going to have to drink about two and a half liters per day. Those calories don't come in the form of useful stuff like glucose and fat: it's mostly protein from red blood cells. Dracula would ... suffer from chronic acidoketosis.

Think of it as the Atkins Diet From Hell.

Plus, of course, blood is salty, about 9 g/liter. So 2 1/2 liters per day of blood will provide about 22 g/day of salt. This is nearly 4 times the recommended daily maximum, and is the equivalent of drinking about 2/3 liter of seawater. Particularly in a limited-water PAW (Post-Apocalyptic World) a diet of blood is likely to lead to kidney failure in fairly short order.

Furthermore, the available market is going to be quite small. The current standard for blood donations is 1 pint/8 weeks, which is the equivalent of 1 liter / 18 weeks. Assuming Stross's 2 1/2 liters per day, that will require the services of 1 employee for 45 weeks, or 315 employees per customer. Even going for 1 pint per week will only drop the ratio to 40 employees per customer, and the employees are going to start dying pretty quickly - not to mention being too weak to do any farm work. The Mayo clinic is current recommending 1 donation per 12 weeks rather than 8, due to depletion of ferritin in the blood.


Very bad idea using human blood as nutrition.

1- Blood cannot be stored easily for later use. You need blood banks for that. Blood takes up too much space, is too heavy and too messy for storage.

2- Blood may contain pathogens that would spread to the drinking person. You don't want to get kuru like that. * shudders *

3- Any small wounds in the mouth or stomach of the person ingesting blood may lead to the spread of such horrible diseases as AIDS, hepatitis B/C, malaria, typhoid, dengue, ebola and whatnot.

4- With all these immense problems in storing and using blood for nutrition, it doesn't help that blood is made very slowly in the body. You can only safely take some 1 liter of blood from an adult healthy human once every 3 months or so.

So no. Really flop idea. Try something else instead.

  • 1
    $\begingroup$ Very important point about pathogens. In a biology lab nearby they have a table surrounded by red tape and a scary warning that they work with human blood there. $\endgroup$
    – Davidmh
    Oct 24, 2015 at 21:24
  • $\begingroup$ It's no surprise some ancient warrior cultures used to dip their arrowheads in human blood that was left in air for 20-30 minutes and then let that dry. Those arrows were reported to cause horrible deaths :( $\endgroup$ Oct 24, 2015 at 21:44

Your warlord has a monopoly on food? I say that this is technically impossible.

This must mean all life outside humans doesn't exist (at least, outside of the warlords sphere of control). Otherwise, there would be some other plants which are capable of supporting some other life which are capable of being eaten.

I don't mean to be macabre, but this has good conditions for a cannibalistic society to emerge. If someone dies, are people who can't get food from the warlord going to just leave that person and also starve to death? They don't have to fight the warlord - they can fight the other people who get food from the warlord and take the dead as their food.

As for what the warlord purposely releases.. It would be easiest to release products such as meat, breads, and milk. Releasing cooked grains or vegetables is possible, but always has some risk of undercooking, even though that risk can be setup to be very, very tiny.

  • 1
    $\begingroup$ To add to this, any kind of processed food would also be fine, things like tofu or corn syrup. Extremely unlikely that such things would contain viable seeds. Hell, you could easily produce roasted seeds as a food that are completely worthless for growing (pumpkin seeds, for example, you don't even need one per fruit to maintain your farms). Just to "rub salt in the wound" as it were. $\endgroup$ Jan 20, 2016 at 18:18
  • 1
    $\begingroup$ The one thing to consider is whether some frankenstein is capable of genetically/chemically re-creating a seed from DNA and the right proteins or other material. Unlikely, but a possible story twist. $\endgroup$ Jan 20, 2016 at 18:21
  • $\begingroup$ Ooh, I like that idea. Nice thinking. :) $\endgroup$ Jan 20, 2016 at 18:24

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