Mr Runciman, who farms near Fakenham, said: A balanced diet and a balanced environment is where we should be. I am not a human nutritionist, but I am a bovine nutritionist so I am well aware that you need a completely balanced diet to get the best performance. If one key part is missing you are going to suffer. You cannot artificially replace all the minerals, vitamins and proteins all the time.
The livestock industry is under pressure to reduce its greenhouse gas emissions, but Mr Runciman pointed to the sustainability of meat as a protein source in a country where 65pc of available farmland is best suited for growing grass for grazing animals, rather than crops for human consumption.