The authority said that advertisements for fast food often "employed hyperbole in order to demonstrate the range of ingredients available to consumers and showed them or the food product in their best light".
It also noted a previous ruling which said that a burger advert which presented a burger in its best light was not misleading, and ruled the Subway advert fell under the same category.
None of the food bought from the major chains yesterday matched how the items looked in advertising. But all said marketing images of their products were designed to show the different ingredients used.
Subway said the image of its 6-inch Subway Club sandwich taken by the Herald was disappointing.
It "isn't what we would normally expect from our stores, and it doesn't look like it has been made to the correct formula", a spokesman said. The company would be following up with the store.
Restaurant Brands, which owns KFC and Carl's Jnr, said all products shown in advertisements and menus were "real products" made with the same ingredients as food served to customers.
Complaints about how food looked were "almost never" made by customers, Restaurant Brands said.
Wendy's chief executive Danielle Lendich said photos of their burgers used in advertising were taken before they were wrapped.
McDonald's said: "Due to practicalities of shooting food, stylists use techniques to ensure the product is looking its best under lights.
"While a product can take hours to shoot, McDonald's prepares food when a customer orders, and delivers it in seconds or minutes," a spokesman said.
Burger King said it aimed to "capture the tastiness of our products via great photography".
Auckland University marketing expert Dr Bodo Lang said advertising agencies went to great difficulty to assemble an "ideal burger" in the studio, using all sorts of tools including lighting.
He said the burger had to be "pretty close to the reality" and agencies were very careful.
- Additional reporting Matthew Backhouse, APNZ
