i had a thought human cells need oxygen and glucose to make energy glucose you get from food however it seems that the digestive system an stomach get shrunk so you wont get glucose from that but cells need it for energy or they wont work.
and with the increase of cells when wearing the armor you need to be able to produce enough energy. the amount of oxygen is increased thanks to the armor but you need glucose since there is no food how will cells make ATP to work and if there was a alternate way you would not need oxygen. the only answer for now i can think of is that the armor produces glucose true matter conversion similar how a nanofactory will work by manipulating atoms the suit goes a step up and uses the building blocks of atoms protons neutrons and electrons to form the atoms it need to form the molecules to form glucose
that way the host cells and guyver unit cells have enough energy indefenitly.
the suit systems can run on the host energy becouse for example using the megasmasher once will put you in a coma it will use every ATP in your body and still wont be enough these systems get there energy from the orb in the waist.
also can someone explain what genetic changes are made to the host becouse the only thing i can think of is the things on his back i dont see any other reason to manipulate and change the host dna.