Do andriods eat?

As I read the book, when I try and visualize the androids, its tempting to think of them as blatantly obvious robots, like c3p0 and r2d2 from star wars. But if people can't distinguish them, then they must look and feel just like humans. I guess instead of bones they have metal inside, yet their flesh is just like human flesh. I can't imagine looking at a person and wondering if they were artificially created. Nothing but electronics, plastic, and metal. The creators must have done a really good job to imitate the physical appearances. But if they were created to be identical to humans on the outside, what about the inside? I wonder if they have a digestive system. Do they eat? Did the makers go so far as to imitate the intimate details as well? If so, why? Is it that necessary to have androids to be just like humans to do the deeds that they were created for? Were they created with the sense as well? Can they smell, taste, touch? If they do have all the senses as humans, does it make them more human?