Many people do not have enough income for a "decent diet", public health experts have claimed in an open letter to the prime minister.
The UK Faculty of Public Health said the situation had become so serious that an independent group should be set up by the government to investigate.
The letter pointed to rising food prices, falling wages and a boom in food banks as proof.
But the government said there was evidence problems were getting better.
Faculty president Prof John Ashton said: "Increasing numbers of people on low wages are not earning enough money to meet their most basic nutritional needs for maintaining a healthy diet.
Professor John Ashton: ''If the current trends go on, we are going to have a malnourished generation''
"We should not accept this in the UK, the world's sixth largest economy and the third largest in Europe.
"An affordable nutritious diet is a prerequisite for health.
"We view the rise of food poverty as indicating the reversal of what was a long process of improvement in food availability and affordability since World War Two
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http://www.bbc.co.uk/news/business-27225323