From Nature:
The World Health Organization (WHO) has issued new guidelines showing how babies should ideally grow. Controversially, the new charts mean that more children in Western countries could be labelled as overweight. Doctors and parents already use charts to gauge if kids are gaining height and weight healthily. But they have flaws; they were drawn up in the 1970s and based on surveys of American children, when most babies were fed formula rather than the breast milk recommended today.
The WHO’s new Child Growth Standards are designed to show how children from birth to age 5 should grow when given a model healthy start in life. Researchers selected 8,440 children from Brazil, Ghana, India, Norway, Oman and the United States who were breast-fed, received good medical care and had mothers who did not smoke. They collected information on their height, weight and other growth milestones over 5 years.
More here.