When my kids were little, I never gave them juice and the Doctor told me to just give water. That they should get used to it.. and juice is so sugary.. So I did.. My kids drink water a lot.. and when they were babies they were rarely constipated and in hindsight now, I feel like it was because they drank so much water.
I think we forget that babies need it too... With their bottles or breast or juice or whatever we are giving them, my kids LOVED a cold water in their bottle or sippy cup..
I know water is MY savior... :)