The hero of my story has been cursed to be forever 'bloodthirsty' in the literal sense of the word. Effectively, he has been turned into a vampire. But drinking blood will cause him to lose his senses, compassion, and empathy, which is why he refuses to drink blood, even though his body thirsts for it and causes him burning pain when he smells it. However, he still gains nourishment from normal food.

Thus, how would I reconcile the fact that hunger, thirst and need for sustenance can be sated by normal food and drink, and yet he still thirsts for blood?

Would drinking blood cure him of the need for normal food? Can he live solely on blood?

Could drinking blood increase his strength beyond what normal means could?

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    $\begingroup$ Replace "blood" with "coffee" and you're question will describe millions/billions of people :) $\endgroup$
    – MonkeyZeus
    Apr 7, 2016 at 17:45
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    $\begingroup$ @MonkeyZeus Replace coffee with Mountain Dew, and you describe the rest of us. $\endgroup$
    – Jax
    Apr 7, 2016 at 17:50
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    $\begingroup$ The "you're" in my first comment is causing me a great deal of angst but I cannot edit it anymore since it's past the 5-minute mark. I apologize en masse to all future visitors :( $\endgroup$
    – MonkeyZeus
    Apr 7, 2016 at 17:54
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    $\begingroup$ @MonkeyZeus: When I run into this annoyance, I simply copy the text, delete the original comment, and paste the text into a new comment, which I can then edit. $\endgroup$
    – jamesqf
    Apr 7, 2016 at 18:44
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    $\begingroup$ @MonkeyZeus - couldn't agree more. sips coffee $\endgroup$
    – AndreiROM
    Apr 7, 2016 at 19:12

5 Answers 5


Consuming blood can be a psychological addiction instead of a physical need

It doesn't have to be a physical dependency. If he can live indefinitely on normal human food, then he's getting everything his body needs in terms of carbs, fats, proteins, vitamins and minerals. However, just because the body has what it needs, doesn't mean that the psyche has what it needs.

The burning sensation in his body could be the result of a projection of his mind. His body is actually just fine, but his mind thinks his body is on fire. We see this kind of projection in some forms of mental illness where a patient will believe their skin is dirty but in reality they've "cleaned" their skin so much that the skin is gone.

In addition to this being a purely psychological problem, this poor vampire is in a state similar to "dry drunkenness" or "white knuckling", a state familiar to anyone with alcoholism. He's given up blood [alcohol] but his mind desperately, desperately wants it. Extraordinary feats of will-power keep this vampire from taking that first juicy bite. The inevitable problem with dry drunks is that they start drinking again. In the context of this story, this vampire is in a desperate "man vs self" style conflict....which could get really interesting.

  • $\begingroup$ This reminds me of the show Being Human (the UK version, don't know about the US version), where the vampire character is essentially a recovering blood addict. He doesn't need blood, he just really, really wants it. $\endgroup$ Apr 7, 2016 at 14:14
  • $\begingroup$ @DaaaahWhoosh i thought of heroin addiction when I was writing this. $\endgroup$
    – Green
    Apr 7, 2016 at 14:15
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    $\begingroup$ @ASH-Aisyah, a psych addiction gives you a lot of leeway to play with. The mind is capable of inventing all manner of things. $\endgroup$
    – Green
    Apr 7, 2016 at 14:59
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    $\begingroup$ @ASH-Aisyah, I added in some additional information about dry drunkenness that may be useful as a plot driver in your story/world. $\endgroup$
    – Green
    Apr 7, 2016 at 15:04
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    $\begingroup$ @ASH-Aisyah, I was referring more to the pattern of dry drunkenness where a drunkard/vampire desperately wants to drink alcohol/blood but just as desperately does not want to. It's an incredibly powerful urge and the mind can invent all manner of physical symptoms to overcome the willpower to not drink. $\endgroup$
    – Green
    Apr 7, 2016 at 15:09

Well a normal human can live a long time on bread and water. However, they aren't going to be very healthy. I would say that the normal food is sufficient or barely adequate to sustain him (as a vampire). A rare steak might help him out a little more, or blood sausage.

I would expect that the constant need for blood is either a curse that tortures him or that consuming blood powers some of his supernatural abilities. When he does drink blood it may also give some kind of high like heroin, making it harder to resist.

  • $\begingroup$ Thanks bowlturner! But hmmm, how would the blood power supernatural abilities? $\endgroup$
    – ASH-Aisyah
    Apr 7, 2016 at 14:40
  • $\begingroup$ @ASH-Aisyah Well he's cursed and that is supernatural. And blood has always been believed to hold mystical powers so... $\endgroup$
    – bowlturner
    Apr 7, 2016 at 14:51
  • $\begingroup$ hahaha, yes true. Sorry, I meant more to the physical side of things. Would something in the blood unlock some sort of mental box that gives him powers? Because physically, blood (or anything that we eat/drink) just gets digested... $\endgroup$
    – ASH-Aisyah
    Apr 7, 2016 at 14:56
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    $\begingroup$ @ASH-Aisyah it IS a cliche - and because it is, you really don't need to justify it! Just have your characters accept it happens without question, and your readers will too. That said... Maybe vampires grow an additional organ, that absorbs the blood from their intestines and converts it into something else. I think your real problem, is you want to find a way to make the impossible possible, and the only way to do that is to change the rules of reality. Like, what if all humans in your reality have phlebotinum in their blood, and it reacts to a vamps digestive juices? $\endgroup$
    – Benubird
    Apr 7, 2016 at 16:04
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    $\begingroup$ @ASH-Aisyah - have you ever had a sugar/caffeine high? I remember how I would feel when I first started drinking coffee. The colors would feel more alive. I could focus on my code with seemingly incredible clarity. All my senses felt enhanced, and I even felt like I was floating a little bit when I walked (I started drinking coffee at around 25, never tried it before then because I thought it was disgusting). Blood could easily have the same effect on your hero: the ability to move faster, focus on his surroundings, sharpened senses, etc. After the high he could be exhausted however. $\endgroup$
    – AndreiROM
    Apr 7, 2016 at 19:18

In answer to your questions about living on blood and getting extra strength from it, the answer is categorically no on both.

Blood has a lot of nice vitamins which are handy for long-term health, but it's totally lacking in calories. A vampire living solely on blood would die of starvation, and in about the same time as a regular person would starve to death. Even if you hypothesise a different digestive system, it still doesn't work. There simply isn't enough chemical energy in there to be extracted. That also kind of screws up the extra strength option too.

Of course hysterical/berserker strength is a thing, so some kind of brainwashing to tap into that when exposed to blood might be possible. But that's just accessing strength they already have and don't use.

And of course you could invoke magic. Vampires drink blood because of narrative necessity (otherwise you wouldn't have a vampire in your story!) and magic can provide enough handwavy depolarise-the-positronic-fields-Scotty guff for temporary suspension of disbelief.

  • $\begingroup$ A narrative necessity, plus one. - Is it a vampire or not? Idea generation is off-topic. The OP either needs to ask for historic precedent or provide us with their narrative so that we can shoot holes in it. $\endgroup$
    – Mazura
    Apr 8, 2016 at 2:21
  • $\begingroup$ "but it's totally lacking in calories" Wait, but how then RL vampires (vampire bats) survive on blood? $\endgroup$ Feb 20, 2019 at 5:59
  • $\begingroup$ @user161005 I should clarify then - it's got nothing like enough calories for a larger animal. Vampire bats are tiny, and they need to drink so much blood that the volume of liquid would cause organ failure for any other animal; their kidneys have adapted to it. Ticks and other biting insects also live on blood, of course. But you can't sustain a larger animal on blood, because the calories aren't there. $\endgroup$
    – Graham
    Feb 20, 2019 at 10:21
  • $\begingroup$ What prevents us from scaling up, say, a vampire bat? They already evolved to compensate low calories by consumming bigger amount of blood. $\endgroup$ Feb 20, 2019 at 10:26

You could make it so that blood is simply a craving.

A lot of people crave sugar and fatty foods despite the fact that they offer little nutritional benefit and have lots of downsides, yet people still eat plenty of them and it makes them overweight and causes plenty of issues such as type 2 diabetes.

Sugar does actually provide energy in moderate quantities, and gorging on plenty at once can make one hyperactive. Having absolutely no sugar in a diet can equally cause problems, or mean that the person has little energy.

So substitute sugar or fats for blood and it's a similar scenario. Maybe lack of blood would make the vampire lack certain things, they may become some form of malnourished without blood, or are affected more by sunlight, but can still survive reasonably well.

If they moderate their blood intake then they can be completely healthy, but when they drink blood they will obviously crave more, which can soon cause them to get out of hand and they become addicted to it. Then an excess in drinking blood, rather than making them overweight would cause them to have less humanity and morality.

Maybe certain vampires have no blood in order to ensure their systems are not used to it, then they have parties where they gorge on blood and temporarily become incredibly energetic/strong/nigh-immortal.

There are people who exist almost solely on sugar and fatty foods, and whilst they are not particularly healthy they can continue to survive for a long time. So perhaps a vampire can exist solely on blood, but again it causes a number of issues.

  • $\begingroup$ Perhaps the right form will make the character reasonably sated for a long time. Raw steak, anyone? $\endgroup$
    – Peter S.
    Apr 7, 2016 at 14:15
  • $\begingroup$ Thanks Mike! However, the character in this case 'gains nourishment from normal food', so basically, even if he doesn't drink blood, nothing will happen to him. Yes, he craves it, like 'a lot of people crave sugar and fatty foods', but the lack of those fatty or sugary foods do not cause them physical pain. Also, 'drinking blood will cause him to lose his senses, compassion, and empathy, so he refuses to drink blood'. Physically and mentally, he would become a monster if he drinks blood at all. $\endgroup$
    – ASH-Aisyah
    Apr 7, 2016 at 14:38
  • $\begingroup$ Sugar doesn't make you hyperactive. $\endgroup$
    – Molag Bal
    Apr 7, 2016 at 17:13
  • $\begingroup$ Well, it makes small children bounce off the walls for a few hours. $\endgroup$
    – JDługosz
    Apr 8, 2016 at 1:43

A good model here might be human corn eaters.

A lot of (most?) people consider corn quite tasty, and eating enough of it will make you feel full. However, a person physically cannot live on nothing but corn. It is deficient in two important nutrients, lysine and tryptophan, that the human body requires to process protein and build bones. Trying to do so causes a protein deficiency condition called Kwashiorkor, where people get bloated stomachs, large livers, red hair, and will eventually die. This is why historically societies that relied on corn (eg: Mesoamerica) also had to cultivate beans or some other source food for those missing nutrients.

So for your putative creature, all you'd have to do is change his physiology in a way such that there's a nutrient required for survival that his body is geared to only process out of blood.

One candidate might be Albumin. Its the primary protein in blood, and is usually produced by the liver. So a liver that for some reason quit producing Albumin, or one of several conditions that can cause it to get removed from the body too fast, could be your mechanism. A list of typical symptoms is here. Interestingly, hypothermia is one of them, as are a lot of physical changes that might make a person look ancient.


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