The market for food is of particular interest, as diet is important for a number of different health outcomes. Research in this area involves investigating how consumers respond to changes in prices, or tax rates for different food products, as well as how their purchasing decisions are influenced by public health campaigns or their exposure to marketing. It also considers the way firms adjust their pricing and production decisions in response to policy measures such as taxes on the salt, sugar or fat content of food products, and how these measures might affect the way firms innovate.