Jamie Oliver has accused the Prime Minister of using cost of living crisis as an "excuse" for not tackling obesity
The celebrity chef presented an Eton Mess dessert opposite Downing Street on Friday morning in protest over the government's U-turn on halting 'buy one get one free' (BOGOF) offers on junk food.
A long-time healthy eating campaigner, Oliver praised Tesco for pledging to ban the deal from this October after the government postponed the ban for a year.
He was surrounded by supporters as he embarked on the "What an Eton Mess" protest, in a dig at the PM's school and his U-turn.
But, speaking on a tour of the Hilltop Honey factory in Wales, Boris Johnson argued that while tackling obesity is of "vital importance" the BOGOF offers can help people struggling to put food on the table during the current cost of living crisis.
"There are lots of things you've got to focus on, including diet, eating less, well eating less is the most important thing," he said.
"But there are some things at the moment where we think they make very little difference to obesity and they can affect people's weekly outgoings, people's budgets.
"And at this particular time, if people can save on their food bills with some offers then I think we have just got to be flexible while we continue to tackle obesity."
But Oliver argued the opposite is the case and the offers actually make people spend more.
He said: "This whole strategy was designed by the government and has been researched by the government, proves that this particular mechanic (two for one deals on junk food) makes people spend more of their income and waste more.
"To use cost of living as an excuse is wrong, it's completely unfair. The Eton Mess is symbolic of the mess that we've got ourselves into.
"And actually, if you look at what Tesco said today, they are going to continue on discounts (but on) healthier and sustainable (food).
"They've set the tone and I'm sure others will follow.
"We want to put child health first, the strategy was looking world class and now it doesn't.
"It's our job to put it all back together again and make sure that we can build a better future for our kids."
Oliver famously got Turkey Twizzlers banned from schools across the country in 2005 following his campaign to get schools to serve better quality food.
The processed meaty treats were reintroduced in 2020 with a "healthier" recipe that includes no E numbers and about a 67% meat content.