disclaimer: i don't know if i am right.
so, i remember seeing a video where somebody claimed to be able to drink water and immediately spit it out as water vapor.
i know for a fact that this is impossible but i decided to use high school physics to dig even deeper.
heat, also known as Q is equal to the product of mass (in kg), the specific heat and the temperature change.
Q = mcΔT
when, during a phase transition, the formula used is: Q = mLv
where m is the mass (in kg) and Lv is the latent heat of vaporization (Lv used in this case because the guy claimed to vaporize water.)
assuming the water is at room temperature (20C/68F) ingested is equal to 100grams (0.1kg), the amount of heat needed to make that water go up to boiling point is equal to:
Q = mcΔT
Q = (0.1kg) * (4186J/kg*K) * (80K) = 33488J
4186J/kg*K is the specific heat of water.
and for the phase transition:
Q = mLv
Q = (0.1kg) * (2260000) = 226000J
2260000 is the latent heat of vaporization of water.
adding them up we get Qtotal = 259488J
heat can be defined as the energy that something has to use to heat up the water until it completely vaporises.
259488 joules are roughly 62000 calories.
on average a person consumes 2000 calories a day, so it's near impossible to consume so much energy and not even being able to eat enough food to create it.