All-you-can-eat restaurants are taking over the high street. Here you'll find limitless servings of food for a fixed price - and we Brits just can't get enough. Narrated by Jonny Vegas, this one-off documentary features the extraordinary diners who can eat four days of calories in one sitting; and the canny restaurateurs who know every trick going to fill us up quickly. Welcome to the world of the all you can eat - the fad diet that Britons are really getting stuck into.