David Cameron is urging Britons to "respect" their food more rather than just "shovelling" it down.
David Cameron urged people to take time over food
Giving his support to the "slow food movement", the Tory leader said it was important to "take food seriously".
He said it was time for "an honest debate" about attitudes to food in Britain because it affected so many areas of life.
This included carbon emissions from transporting food around the world to the strain on the NHS from obesity.
Children's behaviour and attention at school could be affected by sugary food and drink, and family togetherness was being replaced by microwaved meals for one, he said during a visit to a farmers' market in East London.
"[Food] matters to our countryside, as small local producers struggle to compete with large multinationals," he added.
"London may be home to some of the world's best restaurants, but as a nation we just don't respect food enough.
He praised the European "food culture," which he said was as lacking in Britain, where "too often, we treat it like fuel, shovelling any old food down, any time, any place, anywhere."
While some people said junk food was at least cheap food, Mr Cameron said it was false economy - "there's a price to be paid for it - in our health, our environment, and our culture."
He urged people to take the time to prepare fresh food.
"This is above all a cultural issue, it's not something that politicians can deal with just by passing laws and launching initiatives.
"Food is not just a state responsibility - it's a social responsibility."
He mentioned that business, government and individuals could "create a culture that respects food".
He said the Conservative policy review was looking at ways of addressing access to fresh, quality food in many neighbourhoods, as well as methods to improve cooking skills, knowledge of food and the basic principles of nutrition.
Marketing to children also needed to be further controlled, not just on television, but also through texts, promotions and sponsorship.
Tory delegates at their party conference voted in support of outlawing junk food ads on TV and other promotions aimed at youngsters.
"Food is one of the great pleasures in my life, and I always try to make time for it," said Mr Cameron, who chose fellow Old Etonian Hugh Fearnley-Whittingstall's River Cafe Cookbook on Desert Island Discs.
The Tory leader said he grows vegetables and "always" cooks Sunday lunch for his family and friends, but added that he sometimes succumbed to the temptations of junk food.
"None of us is perfect," he added.