In fact, this view is contrary to the current "UN Breastfeeding New Perspective" put forward by UNICEF. The new view is that, under normal circumstances, breastfed infants do not need to add any food or drink within 4 months; including water. There are six major types of nutrients needed for human growth and development: proteins, fats, carbohydrates, vitamins, minerals, and water. The first three nutrients can produce heat, known as the production of nutrients; the latter three can not produce heat, called non-productive nutrients. Breast milk contains all the nutrients needed by the baby within 4 to 6 months. It contains not only the protein, fat, and lactose needed by the baby, but also sufficient vitamins, water, iron, calcium, phosphorus, and trace elements. . The main component of breast milk is water, which is enough for infants. Furthermore, infants within 6 months, when the amount of breast milk is sufficient, heat and moisture can fully meet the metabolic needs of the baby, so breastfed infants do not need to feed warm water. Feeding additional water will increase the burden on the baby's heart and digestive tract, which is not conducive to infant growth and development.
Of course, infants with pathological conditions, such as a high fever; dehydration of diarrhea, or taking sulfa drugs, or sweating in summer, must be warm water to compensate for the loss of body water.
In the past, many mothers had to add warm boiled water between two feedings of their baby. They think that feeding one more time between feedings can prevent children from dehydrating.