Mr Brown, 31, announced yesterday that he is leaving Loaded to become editor of the upmarket GQ which sells over 200,000 fewer copies a month than Loaded.
Conde Nast, publisher of GQ, denies that Mr Brown is planning to change their magazine in order to chase the sales of Loaded.
However, Nicholas Coleridge, Conde Nast's managing director, confirmed that Mr Brown would take the magazine closer to the style it had under Michael Vermuelen, who died two years ago from a drug overdose. Since then the magazine has been edited by the more cerebral Angus McKinnon who resigned from Conde Nast yesterday.
Loaded was launched by IPC Magazines in 1994 with target sales of about 40,000. In the last six months of 1996 its audit sale was around 375,000 and the latest issue are understood to be selling more than 400,000 copies a month.
Mr Brown said: "I won't talk about Laddism and all that bollocks, that shows a lack of understanding of what Loaded is about. I'm not a 25-year- old loafer any more, I'm confronting new things in my life now and GQ will give me much greater scope.
"I want to make the magazine very exciting and funny and full of commanding journalism. It is a natural step on."
Mr Brown and Tim Southwell, both former pop music paper journalists, came up with the Loaded concept and convinced IPC to publish it.
Mr Brown's appointment should inevitably mark a change of direction for GQ. It was launched in the UK in 1988 and stayed stubbornly under the 100,000 sales mark until the men's style magazine market took off on the back of Loaded's success. It has risen steadily to 150,000, but has been eclipsed by EMAP's FHM, which was redesigned in the Loaded mould and is now selling close to 500,000 copies a month.
Loaded is famous for its fixation with naked women, alcohol, drugs and football. Its early journalistic innovations have included a Biscuit of the Month review and a comparison of snack foods, called the Crisp Olympics.
The magazine's editorial staff has made no secret of their love for mind- altering substances, but Mr Coleridge denies he is concerned about James Brown's reputation. "After all we haven't employed Will Self," he said.
Loaded, the sit-com Men Behaving Badly and Nick Hornby's novel Fever Pitch have been credited with creating a culture of Laddish behaviour characterised by a taste for sex, lager and football. However, many argue that Laddism is a media label for something that always existed. Whatever the arguments, the effect has been that even the more up-market men's magazines, such as GQ and Esquire, have been forced to increase the amount of flesh on their covers and in their pages.
Lads' magazines have even been credited with WH Smith's decision in January to withdraw soft-porn magazines from its top shelves because Loaded and FHM had affected their sales.
The lads' magazines have attracted a host of imitators, including Maxim from Dennis publishing and specialist spin-offs such as IPC's Loaded for foodies, Eat Soup, and Stuff, Dennis publishing's "big boys' toys" magazine.
Mr Brown is expected to leave Loaded in the summer. A replacement has yet to be found but David Lancaster, editor of Eat Soup, and Martin Deeson, deputy editor of Loaded, are tipped to succeed him. The changing men's market has caused a switch-around in editors for all the main men's titles. Mike Soutar left FHM last month to become managing director of Kiss FM while Peter Howarth moved from Arena to Esquire to replace The Independent on Sunday's editor, Rosie Boycott.