Sugar is not inherently evil, and provided your juice doesn't have extra sugar added and still has the pulp, it's fine. In fact, if you get a Ninja or one of those small smoothie blenders, you can throw whole fruit in it and "hide" a good amount of vegetables in there without the kiddos even noticing. You'd be surprised how much spinach you can "sneak" in with fruit before they notice the taste. Kale, however, is a very strong flavor, and there's no getting that past them.No, I would definitely stick to water! Anyone who says you need more is flat-out lying to you. Water has all you need for hydration and juice, even if 100% juice, just has unnecessary sugar in it.