Interest in irrigation in sub-Saharan Africa has revived since 2000, in line with the revival of interest in agricultural development and food security in general.

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.

This report sets out the shifts in thinking, debate and approaches on agricultural development over recent decades.

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.

Input subsidies need to be contemplated with caution, with a clear consideration of the costs and benefits compared with conventional best practice of addressing market failures directly and using social policies to address social objectives with respect to poverty and food insecurity.

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.

The current spike in food prices needs prompt reaction through various forms of social protection to avert poverty and hunger. Prices are soon likely to fall somewhat, but not to their previous levels.