Poverty is forcing people to have dangerously poor diets and is leading to the return of rickets and gout – diseases of the Victorian age that affect bones and joints – according the UK Faculty of Public Health.

The public health professionals' body will call for a national food policy, including a sugar tax, as concerns rise over malnutrition and vitamin deficiencies in British children. It will also appeal for all political parties to back a living wage to help combat the illnesses.

Doctors and hospitals are seeing a rise in children suffering from ailments caused by poor diet and the faculty has linked the trend to people's inability to afford quality food. Latest figures show there has been a 19% increase in people hospitalised in England and Wales for malnutrition over the past 12 months but experts say this is only the extreme end.

Dr John Middleton, from the FPH, said the calls would come in the faculty's manifesto to be published next month and warned that ill-health arising from poor diets was worsening throughout Britain "through extreme poverty and the use of food banks".

He saidthat obesity remained the biggest problem of food poverty as families are forced into choosing cheap, processed high fat foods just to survive. "It's getting worse because people can't afford good quality food," he said. "Malnutrition, rickets and other manifestations of extreme poor diet are becoming apparent. GPs are reporting rickets anecdotally in Manchester, the East End of London, Birmingham and the West Midlands. It is a condition we believed should have died out.

"The vitamin deficiency states of gout, malnutrition being seen in hospital admission statistics are extreme manifestations of specific dietary deficiencies or excesses, but they are markers of a national diet which is poor. Food prices up 12%, fuel prices up double-figure percentages and wages down is a toxic combination, forcing more people to eat unhealthily."

He said many policy makers forgot the impact of rising energy prices on diet. "That is the bit people dont really appreciate - a processed meal from a supermarket will need less feeding the meter as of course will a fast food take out. Poor people are having to pay out more of their income on food compared to the better off. There are difficult choices for people on low income."

Carmel McConnell, founder of the Magic Breakfast charity, which provides a free breakfast to 8,500 British schoolchildren in need each morning, said teachers in the schools she worked in expected to see a dramatic decline in the health of their pupils as they return after the holidays: "Teachers tell us they know even with free school meals it will take two to three weeks to get their kids back up to the weight they were at the end of the last school term because their families cannot afford the food during the holidays."

McConnell and Middleton both welcome the Nick Clegg-led intiative to start universal free school meals in schools for younger children, although critics are claiming that schools, already facing a dire shortage of places, may find it difficult to accommodate when the scheme is rolled out later this week.

The UK has 3.8 million children in extreme poverty. Charities such as the Trussell Trust report growing need for food banks but say that some of the items donated can be of poor quality.Dr Middleton said: "If the nutritional diseases are markers of a poor diet, the food banks are markers of extreme poverty - the evidence from Trussell Trust suggests the biggest group of users are hard working poor families who have lost benefits, live on low and declining wages and or they have fallen foul of draconian benefits sanctions which propel them into acute poverty and hunger. This is a disastrous and damning indictment on current welfare policy and a shame on the nation. The food banks are providing a real and valued service staving off actual hunger – they are actually keeping people alive."