Sales at Pizza Hut and TGI Fridays have suffered badly in the 24 weeks to 18 August, as increasingly frugal consumers rein in their spending.
Pub restaurants, where Whitbread has now completed the rebranding of all Brewsters outlets to Brewers Fayre, also suffered with a 1% fall in like-for-like sales over the period.
Overall, group like-for-like sales increased 0.6%, with total sales up 12.5% thanks to the healthy performance of newly integrated budget hotel chain Premier Lodge.
Stripping out the positive effect of Premier Lodge total sales were up 4.5%.
Whitbread chief executive Alan Parker said: "In a difficult trading environment we continue to grow sales, which is a testament to the underlying strengthen of our business, and the benefit of the Premier Lodge acquisition."
Parker also announced that Whitbread would be returning an additional £150m to shareholders as part of its Marriott disposal programme, bringing the total windfall to £400m.
Two new senior appointments were also announced. Mike Tye, currently managing director of Premier Travel Inn, will take on the same role at David Lloyd when Stewart Miller steps down on 30 September.
Filling the position vacated by Tye, Patrick Dempsey, previously managing director of Whitbread's Marriott division, will take over at the budget hotel operation.
By Chris Druce
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