Do your feces normally smell foul? If not, you're getting rid of something you normally don't expel. If you have fatty liver, you have many many Liver Flushes to do before you regain health. Might be better not to do them right after a fat-free fast -- your liver stops producing bile if you aren't eating any fat at all. The flush might be better if you preceed it with a low-fat high fiber diet.
Water fasting is extreme. To nourish your healthy body, you need vitamins and minerals that wash out every day and thus, need to be ingested daily. A periodic cleanse is ok, but it needs to be preceeded by weeks of healthy Diet and followed by a committment to healthful eating.
Your digestive tract has been artificially modified, so it is harder for you to absorb the nutrients your body needs. Eat six small snacks every day, each one nutrient dense foods, high in fiber but low in fat and starch. You may need additional vitamin/mineral supplements if you had intestines removed. Without a gallbladder, you might do better taking digestive enzymes with every meal.
Fresh veggie juices are terrific in your situation -- easy to digest and easy to assimilate the nutrients. Focus on "above ground" veggies. Root veggies have more carbs and sugar. Use 25% juice of root veggies, maximum, in the mix. Broccoli juiced together with a whole lemon and an apple is terrific! Dilute it to taste with water. Add a Tbs of flax or fish oil to make it easier for your system to absorb the fat soluble vitamins A, D & K in the broccoli.
Perhaps your next fast can be a veggie juice fast -- nutrients to support health, but easy on your digestion to let your system rest and recover.