Compass Group UK & Ireland chief executive Don Davenport is to retire from the company on 30 September.
The 62-year-old will be replaced by Peter Harris, chief executive of the group's ESS Support Services, Middle East and Africa division. Harris will lead a newly merged UK, Middle East and Africa division.
Davenport, who also plans to step down as chairman of People 1st and Hospitality Action, said: "I've been thinking about it for a long time. The merging of the two divisions makes sense."
In further restructuring, human resources director Clive Grundy will also go, but will not be replaced, as divisional HR managers will cover the work.
Compass Group company secretary Ron Morley has also lost out in the reshuffle. His role has been merged with that of Tim Mason, company secretary for Compass's UK division, who will take over the new combined position.
The departures follow a rocky financial period for the world's largest food service group, which included two profit warnings in seven months.
The company is currently undertaking a business review in order to cut £50m in costs by 2006. Some industry sources believe that Davenport, Grundy and Morley may not be the last to leave.
Food service consultant Chris Stern said there was bound to be further fall-out. "He was such a dominant figure, and his departure marks a complete change of culture."
But the City was fairly unexcited by the departures. "It's fairly minor news in terms of the share price," said Wasserstein Kleinwort Dresdner analyst Karl Green.
Meanwhile, City analysts have played down rumours that Compass may be taken over by Raphoe Management, the investment vehicle of Gerry Robinson.
Speculation has linked the former Granada boss with the company because of his knowledge of the business. Robinson and Compass chairman Sir Francis Mackay led the group's buyout from Grand Metropolitan in 1987.