Dear Robyn,

Interesting questions about the projections into eternity of the necessities for continued existence in mortality. Without food or periodic rest in mortality we, of course, could not survive. We would die and pass into eternity. In eternity we will first live as unembodied spirits, and then at the resurrection our spirits will be clothed with the physical bodies we had in mortality, with the modification that the bodies will now be immortal—not subject to death. Instead of blood flowing in the veins, there will flow a spiritual material that I imagine will sustain the body in eternity in somewhat the same manner as the blood gives life to the body in mortality. The immortal bodies, as tabernacles of the eternal spirit, will continue to exist forever, without end.

Brigham Young had something to say about how the spirits may live after mortality.

“We shall turn round and look upon it [the valley of death] and think, when we have crossed it, why this is the greatest advantage of my whole existence, for I have passed from a state of sorrow, grief, mourning, woe, misery, pain, anguish and disappointment into a state of existence, where I can enjoy life to the fullest extent as far as that can be done without a body. My spirit is set free, I thirst no more, I want to sleep no more, I hunger no more, I tire no more, I run, I walk, I labor, I go, I come, I do this, I do that, whatever is required of me, nothing like pain or weariness, I am full of life, full of vigor, and I enjoy the presence of my heavenly Father” (Funeral sermon 14th Ward, July 1874, JD17: 142). 

Apparently we will have no need for food— “I thirst no more, I hunger no more,” nor for sleep— “I want to sleep no more, I tire no more.” It will be marvelous to learn, when we get there, of the wonderful abilities of the spirit in the spirit world. Here is another interesting quotation from Brigham Young that explains some of the other abilities of the spirit,

“The brightness and glory of the next apartment is inexpressible. It is not encumbered so that when we advance in years we have to be stubbing along and be careful lest we fall down. We see our youth, even, frequently stubbing their toes and falling down. But yonder, how different! They move with ease and like lightning. If we want to visit Jerusalem, or this, that, or the other place—and I presume we will be permitted if we desire—there we are, looking at its streets. If we want to behold Jerusalem as it was in the days of the Savior; or if we want to see the Garden of Eden as it was when created, there we are, and we see it as it existed spiritually, for it was created first spiritually and then temporally, and spiritually it still remains. And when there we may behold the earth as at the dawn of creation, or we may visit any city we please that exists upon its surface. If we wish to understand how they are living here on these western islands, or in China, we are there; in fact, we are like the light of the morning” (Discourses of Brigham Young, p.380).