It would stand to reason that if a person is fasting strictly for weight loss, ( and is quite overweight) there is a chance s/he already has a fatty liver--depending on diet, etc.
Water fasting goes best with a good diet. I do not personally see it as a replacement for liver flushing. I've done maybe five liver flushes, and it has made a huge differnece in my overall health and vitality. I did four of these before doing my first Water Fast (of 29 days). Possibley that explains in part how the fast was relatively painless and quite easy.