A resurrected body is an immortal body and will not require food to sustain life. The makeup of our bodies now are built to have the food we eat sustain our lives. Perhaps when we resurrect, the inner function of our bodies will be different than our mortal bodies. Maybe they will be able to burn up all the food we eat and not have to excrete it. Then again, maybe resurrected being do excrete. We don't know for sure. We do know that Jesus ate after appearing as a resurrected body to his disciples. So the ability to eat is still with us.
Luke 24:36-43
36 And as they thus spake, Jesus himself stood in the midst of them, and saith unto them, Peace be unto you.
37 But they were terrified and affrighted, and supposed that they had seen a spirit.
38 And he said unto them, Why are ye troubled? and why do thoughts arise in your hearts?
39 Behold my hands and my feet, that it is I myself: handle me, and see; for a spirit hath not flesh and bones, as ye see me have.
40 And when he had thus spoken, he shewed them his hands and his feet.
41 And while they yet believed not for joy, and wondered, he said unto them, Have ye here any meat?
42 And they gave him a piece of a broiled fish, and of an honeycomb.
43 And he took it, and did eat before them.