After being re-elected with an increased majority in the 2015 General Election, McCarthy nominated Andy Burnham in that year's Labour leadership campaign. She was appointed by Jeremy Corbyn as Shadow Secretary of State for Environment, Food and Rural Affairs in September 2015. She argued in a Spring 2015 interview with "Viva!life", a magazine for vegans, that meat should be treated like tobacco, with "public campaigns to stop people eating it". Tim Bonner of the Countryside Alliance said her opinions "are completely out of step with the vast majority of people". "The world is not going to turn vegan because I am in post", McCarthy said on BBC Radio 4's "Farming Today" shortly after her appointment. "I have my own personal views on what I choose to eat, but I accept that we have a livestock industry in this country. What I want is for the industry to have the best welfare standards possible, to be sustainable as well as economically viable."