According to (at least) one version of superstring theory, everything is energy and matter is just wrinkles in that energy which make it seem to be matter.
Everything from plants, light, metals, gasses, electricity, stars, human thought and perception, and literally everything is made of these energy wrinkles. If this were true and could be harnessed, the human mind could change whatever it wanted into whatever else it wanted.
Need food? Turn dirt directly into a steak. Need water? Pull water molecules directly from the air and into your mouth. Need money? Turn your #2 pencil into a diamond or gold to sell. Or just wrinkle the superstring theory energy into those items directly. Maybe you just want to be Neo and fly while stopping bullets, sure why not? At this point, there's literally nothing you couldn't do.
I don't have the resources ATM to find the video I watched about this (probably on YouTube, might have been a TED Talk), but I'll try to find it later tonight.
As impossible as the OP's question sounds, it has a basis in real science. Given enough technology, we could do this. This even gives credibility to the idea of humans evolving into pure energy beings, which is the basis of a wide range of existing science fiction books.
This even has a basis in ancient religion. Buddhism (alive and practiced today) believes that everything is connected through energy, and that given enough meditation, concentration, and training, we can harness this energy to do whatever we want. Sound familiar?