I am never gonna concede that replicators (or transporters) actually convert mass into energy and back. That's insane. Here's why.
Assume you have been cryogenically frozen, and the Enterprise crew has reluctantly awoken you to a world of condescension. You would very much like to eat a chicken tender. Commander Data says you can replicate a .1kg human nutritional supplement no. 96 (known on ancient Earth as a "chicken tender") via a mass-energy-mass process. But wait, you say:
1)You can't just convert mass to energy. You could accelerate it to near the speed of light and smash it into something, I guess. But realistically, I suppose you can throw antimatter at it--but that still winds up with less energy than you had mass due to the creation of neutrinos.
2)Okay, assuming you can "just" convert mass to energy, or don't care about the antimatter that already cost you vast inefficiencies to produce, you now have perhaps a dozen thermonuclear bombs' worth of energy instead of my chicken tender. Even if you are containing this somehow, you must have a fiber optic tube full of several exajoules worth of gamma rays.
3)Assuming you can contain and channel that energy, confining it to the point that it results in spontaneous creation of mass, you don't get matter alone. Instead of my chicken tender, I have a plasma made of quarks, antiquarks, and gluons (and electrons and positrons flying every which way as well). This does not taste as good.
4)Assuming you can manipulate the weak force parity violation that may or may not be responsible for baryogenesis and the dominance of matter, you will not be able to produce the heavy atoms like carbon and oxygen molecules that constitute most of my chicken tender's mass. You're just going to get hydrogen, maybe with some helium and a sprinkling of lithium thrown in.
5)Assuming you can then fuse the resulting H and insubstantial He, and Li ions to get heavier atoms, you still have to recapture all the electrons that are thrown everywhere. I do not want my chicken tender to be ionized please.
6)Assuming you've thrown equal antimatter against at least a half-chicken tender mass, confined the resulting gamma rays and either forgotten about the neutrinos that make up nearly 60% of the reaction products or found a way to use them; gotten around the pair-production problem; reenacted nucleogenesis in order to build up atoms all the way up to iron (an endothermic process); recaptured all the electrons; and then used very precise force fields and extraordinarily powerful computers to rearrange these atoms into molecules, cells, and finally muscle tissue...
7)Congratulations, future, you just spent an astronomical amount of energy, with wastage on the order of at least 60% and probably much, much more, on a
chicken tender.
And not even a very good one, either, to listen to them complain.