Whoops, did I say "liver fast"? I meant liver cleanse. It's actually a cleanse to help clean out the liver and gall bladder, which includes olive oil, Epsom Salts
and a rough night of sleep unless you use a natural sleeping aid. In the morning you flush quite a bit out. It helps ease the body into fasting, as you're not quite as toxic and also because fasting can cause gallstones.
The only thing with the smoothies, like I mentioned before, is that they will promote digestion so you won't actually be fasting. You'll be on a very low-calorie, primarily liguid type diet. But if you've done this before and have noticed positive results, I don't see the harm. You could (and should) also throw in protein and as many vitamins and herbs as you'd like since your body will be able to digest them. This is still also a detox program, just at a much slower pace than actual fasting.
Hope this helps!