However, some interventions cost nothing.
One of the authors of the Lancet series, Gary L. Darmstadt, described successful efforts by a team of U.S. and Indian researchers to change behavior in a region of 300 villages and 100,000 people in the state of Uttar Pradesh in northern India.
Traditionally, women who have just delivered consult a Hindu holy man called a pandit on when to start breast-feeding. After checking astrological tables and other sources, the pandit generally advises that feeding begin two or three days after birth. Until then, the baby is given tea or sugar water.
Many new mothers also squeeze out of their breasts and discard the thick, antibody-filled, disease-preventing first milk, known as colostrum, because it is mistakenly considered old and dirty.
One of the pandits in the area was a physician. After gaining his trust, the researchers asked him to consider changing his advice.
"We just leveled with him and said: You're a medically trained person; you know that breast-feeding is critically important," recounted Darmstadt, of the Johns Hopkins University's Bloomberg School of Public Health.
The man agreed, and he persuaded five other pandits serving the area to change their advice, too.
"I think, in essence, he took an evidence-based approach," Darmstadt said.
