Yes its fine but most people cant cope with sticking to a mostly raw juice diet since it gets tiring but you can try. You can at least implement a fresh fruit juice in the morning and lets say a carrot juice with some greens in it in the afternoon/evening and then bring some solids for fiber.
These 60 day juices diets are mainly a juice fast. Where you deprive your body from food therefore it can detox it self while still giving it nutrients from juices. Why does the body detox well simply because digestion take sup a lot of energy in the body and since most humans constantly eat, the body is constantly digesting and therefore never resting up just like we all like resting it hardly does, so when you fats it finally gets the time to focus on more important issues in the body and detoxifying and healing.
You can try a 2 day juicing fast do research and see if you like it then you can try 2 weeks and so on. But ya its healthy, i myself would do it but after it i would always bring back healthy oils and healthy seeds like flax chia. Certain grains are good but not like wheat unless you buy sprouted which is better, i was talking more like quinoa, millet, amaranth, buckwheat, barley, rye, oat meal ect..