Broadsheet thanks letter writers for pointing out some misleading conclusions I made about the percentage of people for whom anorexia is genetic. As "Doug in India" clarified, although "scientists have deduced that 56 percent of anorexia is genetic [this] does not imply that 44 percent of anorexia sufferers are anorexic exclusively due to environmental conditions."

The percentages are useful scientific shorthand, but it is a mistake to ascribe the breakdown to the general population. Plus, even if a person is predisposed to anorexia, that does not mean that he or she will have it; environmental, psychological, genetic and other factors can trigger one another in a complex interaction.