The theme is a response to the digital advertising sector suffering its first ever recession, according to IAB marketing director Kieron Matthews.
"We're conscious that a lot of advice is being thrown at brands as to what they should be doing in a recession and we believe that nobody really knows.
"But what we do know is that brand strength is really really important so the whole theme of the conference is how to have a fit brand in 2010 and what the media diet is to ensure you maintain that strength in a highly competitive market."
Aimed at digital marketers the event will include an insight into how COI, the UK's biggest spender on advertising, is reorganising to accommodate digital in a speech by its new chief executive Mark Lund.
Matthews adds that marketers will get their first look at UKOM, the new panel-based online audience measurement system from The Nielsen Company due to launch in January. Guy Phillipson, chief executive of the IAB, and Louise Ainsworth, EMEA managing director of Nielsen Online, co-present a session explaining its workings.
Best-selling author Charlie Leadbeater will focus on future trends and is expected to look at how cloud computing will impact on commerce and creativity in the first session of the day.
The impact of the government's Digital Britain strategy could have been a topic, but Digital Britain minister Stephen Timms was unavailable to speak at the event.
Matthews notes that the IAB does not normally invite politicians and last year's appearance by then culture secretary Andy Burnham was the first.
"[Politics] isn't a theme we necessarily go after. The most politically charged thing on our agenda is behavioural targeting and we'll be talking about that in our targeting session along with our online choices and best practice guides."
Perhaps surprisingly, there will be no special focus on social media, which Matthews put down to the lack of proof of social media's impact on brand fitness.
However, the event will wrap up in the company of a social media expert of sorts - arch-Twitterer Stephen Fry will respond to questions tweeted by some of the 650 delegates and share his experience of technology and the internet.
The event takes place between 9am and 6pm at the Mermaid Conference & Events centre near Blackfriars.