The World Health Organization recommends that full-term healthy infants be fed exclusively on human milk from birth to about 6 months of age. That is, they should be given no liquids or solids other than human milk, not even water, during this period.
Babies are programmed to feed when they are hungry and stop when they are full. When they feed like this they will take enough milk to grow normally.
After this initial 6 month period of exclusive breastfeeding, it is recommended that infants continue to be breast-fed for up to 2 years of age or beyond, while receiving nutritionally adequate and safe solids. Starting solids too early or too late are both undesirable. Ideally, the decision when to begin will be made by a mother, based on her infant’s needs.