As low-income countries develop, people’s diets change. They tend to move from being high in cereals (maize, rice, wheat), starchy staples (potato, cassava, plantain) and fibre, to more westernised patterns that are high in sugars, fats and animal-source foods. This has been termed the nutrition transition.

Should the world go on a diet in 2014? There has been a dramatic increase in the numbers of overweight or obese people in the past 30 years. Previously considered a problem in richer countries, the biggest rises are in middle income countries and the developing world.

The international food price crisis in 2007/08 corresponded with significant price increases in domestic markets across the developing world. Prices rose in most Asian countries, but not to world levels. China, India and Indonesia saw no significant increases.

Agricultural prices have fallen heavily since their peaks in the first half of 2008: some are already at the levels seen in early 2007 before the recent spike began. Thanks in part to economic downturn, prices are expected to continue falling in 2009. Prices of inputs such as fertiliser and oil, and ocean freight rates, have also come down; and by even larger fractions than those of outputs.