However Lewis, speaking exclusively to Marketing, conceded the participation of brands in the London 2012 Olympics is "vital to the running of the Games" financially.
"This is hopefully one of the biggest Games from a Team GB perspective and it’s expensive. So brands need to be on board, and good brands are on board," said Lewis, who won gold at the 2000 Sydney Olympics.
"I think [tweeting endorsements] is a dangerous game... I'm not on Twitter and it's not something my coach would have allowed. For me [it was about] less distraction," she added.
Lewis's comments follow criticism of athletes such as swimmer Rebecca Adlington for tweeting endorsements.