Help, please

What are the different types of fasts, their benefits, and lengths? I have never fasted before and I am anxious to detoxify, drop weight, and find overall cleansing. I have been diagnosed rhuematoid arthritis, MRSA, and other infections - possibly due to autoimmune problems. Thyroid is effected by the autoimmune thing, as well! The effects of the Rheumatoid Arthritis are like hitting a brick wall - pain, aches, ridiculous fatigue, etc. So, perhaps fasting will help to kick-start immune system? I don't know much about this and I'm a dry sponge ready to absorb as much information as I can!

Any suggestions will be helpful, though I ask that no product promotion be done, here.

Thanks!