In a move that baffled much of the world, the U.S. tried to shut down a global resolution to encourage breastfeeding.

For decades, research has tended to show that human breast milk — when it's possible to use it — is the safest, healthiest food for babies around the world. A 2016 series in the British medical journal The Lancet — the most in-depth analysis of the health impact of breastfeeding to date — concluded that more than 800,000 babies and 20,000 mothers' lives could be saved each year with universal breastfeeding, at a cost savings of $300 billion.

A mother in the Central African Republic breastfeeds her child while they wait to see the doctor in a clinic with no running water. Photo via Florent Vergnes/Getty Images.