The point is that for these sort of simulations you don't want a general purpose computer. Ideally you have a "equivalent" of the quantum mechanical Hamiltonian that you can manipulate/design and read effects out from. Now to simulate the human body probably requires a prohibitively large number of qubits, however for many very useful things you don't need that.
So my actual knowledge of quantum computing is mostly limited to what I remember from seminars in (physics) grad school, and from listening to my classmates who were actually doing quantum computing research complain about why things weren't working... but this side comment [0] is totally on the money with what I remember. I don't believe we will ever be able to run quantum simulations of interestingly-sized things, though that is certainly an opinion rather than a statement of fact and has a good chance of being inaccurate.
However, any way you look at it, "[quantum] simulating the human body" is complete batshit science wingnut nonsense (though I tried to be diplomatic about it above). There isn't even any way to measure the input state there! It's ill-defined, it's subject to measurement uncertainty, it's just plain chaotic. As an actual former scientist, it would help my blood pressure if science wingnuts who do not understand the first thing about what they're talking about could please stay quiet.
