Let's say I have a roughly humanoid race (similar size, form, activity level, etc.) that spontaneously generates any energy that they need via Magic. However, they still need to eat some materials in order to grow and repair their bodies.

Assuming that their biology is mostly the same to humans, other than the energy generation, how often and how much would they need to eat, and what would be good sources of food?

Their biology has not yet evolved the ability to create matter, and there is an upper limit to the amount of energy they can generate in a certain amount of time.

  • $\begingroup$ Wait, so you mean they simply need the building blocks for their bodies, not the things to actually power the stuff to move those blocks around? Every chemical process that requires energy gets that energy from "magic," and not the usual ATP? $\endgroup$
    – PipperChip
    Nov 8, 2015 at 6:40
  • $\begingroup$ @PipperChip Correct $\endgroup$ Nov 8, 2015 at 16:28
  • 2
    $\begingroup$ How efficient is their magic? Generating a fireball requires an absurd amount of energy in real life, but cleverly levitating an object across the room, a few inches off the ground, does very little work, from the physics perspective. That is, unless you want to play games where things take more or less energy than the actual spell's effect. $\endgroup$
    – Cort Ammon
    Nov 9, 2015 at 0:38

1 Answer 1


It sounds like they need everything except calories for their normal diet. That implies their body chemistry would lack processes for absorbing and storing carbohydrates and to some degree fats (fat is essential to human brains, would likely hold up).

It's up to you whether that means:

  • They could safely eat the same stuff humans do, with all the carbohydrates and superfluous fats just passing through untouched
  • Those things (especially sugar) are toxic to them and they need to get their proteins, minerals, vitamins etc from specific pure foods.
  • They evolved their magic only recently and their bodies still store all calories, causing permanent weight gain if they eat any at all.

In any case, things like mineral clay, plants (unripe fruits?), and select protein-rich parts of animals or other are likely foods.


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