No, Ketosis is not the goal of fasting. Detoxing, rebalancing and healing the body are the the primary objectives of fasting. Ketosis is a by-product in that it happens and is to be expected when fasting.
Understanding the role of ketones in the body and how they are triggered can help relieve some of your anxiety. You're juice fasting, so the lack of calories and low carbs consumed during fasting has dramatic effects on the body’s systems. Because of the lack of glucose consumed, the liver converts glycogen stores into glucose and energy. The brain and the central nervous system need direct glucose, so they must get it either from the breakdown of proteins or fatty acids. The body resists breaking down the proteins, so fatty acids, after being converted into ketones, become the primary source of energy. Ketosis is subdued by drinking plenty of fruit juices, which provide simple carbohydrates for energy and cellular functioning. So if you're overly concerned about the ketones, drink fruit juices everyday, in between your veggie juices. Experiment.
However, if you have a rare condition where you are unable to process ketones (MCAD deficiency), you should not fast. Otherwise, in my unprofessional, yet somewhat experienced opinion, with juice fasting, there is less ketosis (as opposed to other types of fasting and dieting (Atkins, for example), and the simple carbohydrates in the juices are easily used for energy and cellular function.
Hope this helps!
I believe if you drank less fruit juices and more greens, you would lose more weight and have more ketones.
A key to detox: The more juices you drink the less detox, or rather, the slower the detox. The less juices you drink, the heavier the detox. Which is why a water fast is flat out brutal as far as detox is concerned.
So, if you want to speed up the detox, drink less juices and more water. But beware, sometimes the detox is heavy, so maybe plan this when you know you'll be home and near a plump bed to rest.
If you want to speed up the weight loss, drink less fruit juices and more greens (mix with carrot/apple if need be for taste). Of course, always drink an abundance of water (more water than juices). The greens are loaded with chlorophyll and chlorophyll is said to be very nearly like our blood. So, drinking greens adds minerals and chlorophyll which reaches clear to the cellular level in detoxing and healing. Fruits don't boast chlorophyll.