Taking the 2001 book by investigative journalist Eric Schlosser 'Fast Food Nation: The Dark Side of the All-American Meal' as its source, 'Fast Food Nation' differs from most book-to-film adaptations. The book was a non-fiction muckraking exposé of the global and local influences of the American fast food industry; the film is a wide-ranging, fictionalised account of how the industry affects individuals. A heavyweight ensemble cast - check out cameos from Bruce Willis, Ethan Hawke and Luis Guzmán, amongst many others - attempt to make the most of the numerous subplots in Richard Linklater's rambling tale but to very little effect.

There are three main storylines, all of which have plenty of their own offshoots. We first encounter Don Anderson (Kinnear), a marketing executive at a fast food chain called Mickey's (subtle, eh?). Asked to investigate faeces contamination in their burgers, Don travels to the beef supplier's headquarters in Cody, Colorado to take a look around.

Three young Mexican immigrants - Sylvia (Moreno), her husband Raul (Valderrama) and little sister, Coco (Talancón) - are being led across the border en route to jobs in the same slaughterhouse. Ambitious for a better life, they discover that not only are their jobs dirty and gory, but that careless working conditions can lead to life-threatening accidents.

The final story involves idealistic young Amber (Johnson), working in a local Mickey's outlet so she can save money for college. When she starts hanging out with a group of eco-focused college kids, she is caught between her job flipping burgers and trying to release cattle en route to the slaughterhouse.

All these disparate characters are united by their fact that they have roles in the fast food chain - and that's it. Unlike other portmanteau films ('21 Grams', 'Amores Perros' and 'Crash' were recent examples), there is no one event to really pull these individuals together. Despite a few literally visceral moments, the film jumps from story to story in an unfocused manner, never allowing any of the characters room or time to develop into something three-dimensional. Subplots are developed and simultaneously dropped at alarming speed.

Although 'Fast Food Nation' has important things to say, just as Schlosser's book did, without a decent plot to grab an audience it's just preaching to the converted. A missed opportunity.

Caroline Hennessy