Though this is a great practise for greening our lives on this earth, it's also a valuable tool for establishing food sensitivities in babies.
In practising ec'ing (elimination communicating) you can actually see the colour, amount and stream of the infant's/baby's urine. This helps the caregiver to become more aware of which foods cause different colours and volume. Diapers leave caregivers completely unaware of these signs that are valuable in establishing the quality of a child's life.
One of the most important signs of a food sensitivity in an infant is something I call 'peequency'. This is, in my experience, the most valuable sign of all.
For example, if the nursing mother deletes dairy from her diet and the baby experiences lower peequency along with lower spit-up rates, then you've probably got a pretty good sign that dairy is not the best food for that baby.