Taxpayers coughed up more than £7m last year helping to subsidise Parliament's bars and restaurants, a Freedom of Information request has found.
But the taxpayer did have to contribute around £600,000 less than in 2011-12.
Usually the Commons publishes figures that offset sales of souvenirs and gifts against spending on its catering service, making the costs look smaller.
But in response to a freedom of information request, the authorities revealed that without that income the operation ran a deficit of £4.9 million in 2012-13.
That was down from £5.5 million the previous year.
Meanwhile the House of Lords said that, excluding revenue from functions and retail sales, its eight catering outlets cost £2.3 million. That was a reduction of around £18,000.
Prices in the Commons were increased this month in an effort to reduce the burden on the public purse.
A House spokeswoman said: "The cost to the House arises because of the irregular hours and unpredictability of parliamentary business.
"Food and drink prices were substantially increased in 2010 and are benchmarked against similar outlets outside the House.
"The costs to the House have in fact been reduced in each year since 2003 (excepting only 2010/11 when there was relatively little demand during the election period and in one other year), and we are determined to reduce it further."