That was the question posed by Columbia University Professor Arvind Panagariya this year. He argued that genetic differences, not poor nutrition, explain in large part why Indian children are often dramatically underweight and short for their age, compared to global norms.

READ:  India wakes up to child malnutrition ‘shame’

Why, he asked, does India underperform most of sub-Saharan Africa on malnutrition but outperform most of the continent on objective measures such as infant and maternal mortality? Government priorities risk being skewed by poor interpretation of the data, he said.

A girl looks at food served to her for free at a government-run school in Bangalore, India. (AP)

Panagariya's arguments are certainly interesting, but they do not seem to have convinced many nutritionists, judging by half a dozen conversations with experts in the field over the past few weeks.

There are clearly understood reasons that Indian children are underweight: many children are born to young, anemic, malnourished mothers; feeding practices are poor; and their environment is full of fecal matter, in a crowded country where 600 million people have no access to toilets.

Surveys show that most Indian children spend their first few years of life subsisting on carbohydrate-rich but protein- and vitamin-poor diets of just rice or chapati.  Fewer than 10 percent of Indian children under 2 years old are fed a diet of enough variety to meet minimum international quality standards, said Victor Aguayo, head of nutrition at UNICEF, compared to more than half the children in neighboring Sri Lanka.

The low status of women in India is also a big factor. Poor teenage mothers are often uneducated and lack any status in the family, spending more time working for their in-laws than looking after their own children. In Africa, women tend to have more control over household budgets and see their children as their primary responsibility, experts say.

“For me it’s a perfect storm,” said Purnima Menon of the International Food Policy Research Institute in New Delhi. “Everything we know as a driver of malnutrition operates at a very high level in the region.”