Shaun Goater says the Manchester derby means so much that some Man City fans are unable to eat.
City supporters used to sing a chant 'Feed the goat' at Goater when he played for the club from 1998 to 2003, but the former striker believes tension over the fixture is big enough to affect dining plans for fans.
Manchester City travel to Old Trafford on Sunday, live on Sky Sports Premier League, with an eight-point advantage over Manchester United at the top of the table.
"You're talking about the [Manchester] derby, for City fans it's everything," said Goater, who scored a double in the 3-1 win over Manchester United in 2002.
"You know about it weeks in advance, I know certain City fans that can't eat when the game is on.
"They're sick to death when the game is late in the afternoon because they're like, 'I can't eat until after the game'. It means everything to the fans, absolutely everything."
Pep Guardiola's side can equal a Premier League record set by Arsenal in the 2001/02 season for most consecutive wins in a season (14) and Charlie Nicholas believes it would be a "gigantic achievement".
"Like the Arsenal of that time they [Man City] are sensational to watch also," Nicholas told Premier League Daily.
"I think a lot of people who watch the game and love the game probably really enjoy watching Manchester City. There's a certain style and a certain elegance to the way they go about it."