In an open letter to the Prime Minister published in The Lancet medical journal, they stated: "Many hardworking families in the UK are living in poverty and do not have enough income for a decent diet."
The letter, signed by 170 members of the UK Faculty of Public Health (FPH), called on Mr Cameron to set up an independent working group to monitor nutrition and hunger.
The experts also urged him to act on the findings of a yet-to-be-published report from the All-Party Parliamentary Group on Hunger and Food Poverty.
Professor John Ashton, FPH president and one of the signatories, said: "We have to face an uncomfortable truth: we may be facing a public health emergency in the UK.
"The spectre of Oliver Twist is back. Children are going hungry in the UK; they may not be eating gruel but their parents are having to choose cheap food that is filling but not nutritious.
"This crisis can't be explained away by assuming people are not budgeting properly or don't know how to cook.
"There are three main reasons for the increased demand for food banks: increasing food poverty, stagnant income and wages among low-paid people, and the rising cost of food."
He said it was likely that increasing numbers of low earners did not have enough money to meet "their most basic nutritional needs".
He added: "We should not accept this in the UK."