Quantity surveying

Reportedly, University of Leeds research shows that 5.5 billion packed lunches with poor nutritional content are eaten by British children each year (Campus round-up, 21 January). But there were only 9.7 million full or part-time pupils in 2007-08 - that's 567 lunches per child, assuming no one had school lunches and discounting holiday periods. To be charitable, perhaps Leeds has found one of the causes of childhood obesity?

Peter B. Baker, London.