Farmers want "couch potato" removed from the dictionary because they believe the expression is damaging the vegetable's image.
'Inherently healthy', says the British Potato Council
A campaign promoting the use instead of "couch slouch" is being led by the British Potato Council, representing 4,000 growers and processors.
The council argues that potatoes are "inherently healthy".
Protests are due on Monday outside dictionary publisher Oxford University Press and in Parliament Square, London.
"We are trying to get rid of the image that potatoes are bad for you," said council head of marketing Kathryn Race.
"Of course it is not the Oxford English Dictionary's fault but we want to use another term than 'couch potato' because potatoes are inherently healthy."
The campaign is backed by dieticians who say the vegetable is low in fat and high in vitamin C, the council says.
The dictionary defines a couch potato as: "A person who spends leisure time passively or idly sitting around, especially watching television or video tapes."
Chief editor John Simpson said: "When people blame words they are actually blaming the society that uses them.
"Dictionaries just reflect the words that society uses."
Words were never removed from the 20-volume, 650,000-word main dictionary, but little-used ones could be taken out of the smaller dictionaries, Mr Simpson added.
The first recorded use of "couch potato" was in the Los Angeles Times in 1979 and it entered the Oxford English Dictionary in 1993, he said.