You can't live on pineapple & papaya alone. In fact you can't get rid of all parasites with them alone, so why bother?
You need good, and complete,nutrition. What all parasites eat I don't know but I'm quite sure it's not just Sugar as they live in many places in the body and suck up nutrients of various kinds. Don't worry. Just kill them. And eat healthily yourself to keep up your strength.
It's like there are a bunch of rats in the basement. Let them eat what they like, but lace it with poison (herbicides, zapper, etc.) and they will die anyway.