Lately there has been a lot of anguish about the rise in world food prices and how this has affected the nutrition of the poorest. A number of things are to blame for the price rise. In some regions it is bad weather, in particular in the Horn of Africa where there is now a famine.
As long ago as 1974, when grain prices had just quadrupled, the nations of the world promised that by the end of the century 'no child would go to bed hungry'. After a number of years of steady increases in aid for agriculture the momentum slowed. Likewise, in developing countries, the priority given to agriculture seemed to fade away.
Still, that is only a half of it. We don't measure hunger very well. For decades we have assumed that fewer calories means more hunger. A new book, Poor Economics by Abhijit Banerjee and Esther Duflo, turns much conventional thinking on its head.
'What if the poor are not eating too little food?' they write. 'What if, instead, they are eating the wrong kinds of food? What if the poor aren't starving but choosing to spend their money on other priorities?'
They looked at India, 'one of the great puzzles in the age of food crises'. According to government statistics, Indians are eating less; per capita calorie consumption has declined. Why? Incomes are not declining, quite the reverse.
We have to look at this problem of hunger more deeply. Diarrhoea is the scourge of poorer peoples. But it has been an easy problem to solve. The simple use of salt mixed with clean water can revive even bad cases. Hence there is less 'leaking' of the food people eat and therefore less calorie-rich food is sufficient. Also, the widespread introduction of wells, thanks to better boring techniques, has meant that women do not have to walk as far carrying heavy loads of water, usually on their heads. This water is purer and waterborne diseases less common. In sum, less physical energy is expended and fewer calories are needed.