Because of an exclusive sponsorship deal with McDonald's, none of the other 800 food retailers on the grounds of 40 Olympic sites will be allowed to sell "chips or french fries" during the fortnight of the Games. It's part of a contract with the American fast-food giant that gives it exclusivity in the market.
Only McDonald's, Coca-Cola, Cadbury and Heineken will be allowed to sell branded food at the Olympics. The rest will come from local vendors and restaurants.