There's trouble at the top of the burger purveyor to the globe as McDonald's ceo steps down after just seven months in the job.

Charlie Bell was diagnosed with bowel cancer a matter of weeks after his elevation to the top job following previous ceo Jim Cantalupo's fatal heart attack in April. Despite valiant efforts to fulfill his role, Bell has now quit to concentrate on recovering from his illness.

He is being replaced by vice-chairman Jim Skinner who has been with McDonald's for 33 years. His most recent role was head of McDonald's Japan, the group's second-biggest market after the US with nearly 4,000 outlets.

The company, which had been troubled by falling sales over a number of years, has seen a 42% rise in earnings in the three months to September.

The turnaround has been largely masterminded by Bell, aged 44, while chief operating officer under Cantalupo. He offered healthy food options, tightened operating standards in McDonald's restaurants and relaunched the company's marketing campaign under a single global slogan, "I'm Lovin' It", for the first time.

McDonald's is hoping to persuade investors that it's business as usual. A company spokesman says Skinner is "an outstanding leader who will continue the strategic focus established by Jim Cantalupo and Charlie Bell."

Mike Roberts, chief executive of McDonald's USA, has been promoted to president and chief operating officer of the parent company and has been given a seat on the board. He is widely believed to be in line for the top job in the future.

Data sourced from BBC Online; additional content by WARC staff