The Big Challenge initiative is a BBC campaign that aims to encourage people in Britain to make simple changes to improve their health. A two-year initiative from BBC Learning, it runs across television, radio, online and interactive TV and was launched in September 2004 with the TV series Fat Nation.

BBC controller of learning Liz Cleaver said,: "We want to show people that it's not that daunting to get fit and eat more healthily. Small changes can make a big difference and you can have fun at the same time. A vital part of our strategy for Learning is to encourage people to get involved in activities beyond the television programme and going out on the road means we can directly interact with people and really make a difference."

While The Big Challenge is out on the road the site bbc.co.uk/bigchallenge will run a competition offering as a prize a private session with the F-Team from BBC One's Fat Nation: fitness expert Efua Baker, psychologist Dr John Marsden and nutritionist Vicki Edgson, aka Miss Chiplash.

Since its launch in September the Big Challenge website - bbc.co.uk/bigchallenge claims to have attracted up to 500,000 unique users each month and over three million page impressions in total.
85,000 people to date have signed up for a 'personal locker', a private website area which allows them to store information on their fitness achievements.