Communities Secretary Eric Pickles has upstaged George Osborne with a photo of himself enjoying a salad as he puts the finishing touches to a speech.
Mr Osborne has come under fire for tweeting a picture of himself eating a burger on the eve of a big speech.
He defended his choice after it emerged the £10 snack was from restaurant chain Byron, rather than a cheaper takeaway.
The chancellor joked on Wednesday that the portly Mr Pickles was a "model of lean government".
He made the remark during his Spending Review statement in the Commons, after cutting Mr Pickles' Community and Local Government Department by 10%.
Mr Pickles posted the photo - in which he is in an almost identical pose to the chancellor - on Twitter, accompanied by the caption: "Putting the final touches to the LGA [Local Government Association] speech".
Mr Osborne responded to the picture writing: "Nice one Eric."
The chancellor earlier defended his choice of food, saying it was "perfectly reasonable to have a burger while working on a speech".
His Twitter photograph has been criticised by opponents who have said his attempt to cultivate more of a down-to-earth image had backfired.
But Mr Osborne told BBC Radio 4's Today programme that he was equally comfortable "talking about the merits of" a quarter pounder with cheese as a so-called "posh" burger.
"I was working late on a speech and I had a hamburger and the world is now talking about it," he said. "It is perfectly reasonable to have a hamburger while working on a speech."
He said Twitter - which he joined on Budget Day in March - was a new venture for him.
"One of the challenges for politicians, which this incident demonstrates, is that all people see of politicians is in the TV studios or the House of Commons. The point of Twitter is to try and say something about what you are up to during the day."
Asked whether he was likely to relax with a pizza or a curry tonight, the chancellor said it was more likely his evening meal would be "pasta cooked at home... if that's alright?".
Mr Osborne's choice of restaurant was echoed by Deputy Prime Minister Nick Clegg, after he was asked when he had last bought a burger, during his weekly radio phone-in.
After thinking for a while Mr Clegg said it had been "quite an expensive one", recalling that he had gone to a "a burger place called Byron" after taking his children to the cinema.
Mr Clegg added that the main reason for their choice of eaterie was his children's desire for one of their milkshakes.