Government campaigns to improve the nation's diet and health are destined to fail, unless it acknowledges the different domestic routines, relationships and resources which affect how and what families eat, a study has claimed.

Much of the government's policy literature is aimed at individuals rather than families, and doesn't take into account different circumstances, routines and ethnicities, the study by University of Sheffield and Royal Holloway said.

Professor Peter Jackson of the University of Sheffield said that a better understanding of social and cultural conventions was required in order to truly improve the nation's diet. "Although government policy makes some acknowledgement of the impact of poverty and other social factors, this often takes second place to the 'blame' culture," he said.

"People were shocked to see mothers sneaking 'junk' food into schools after Jamie Oliver's intervention, but government needs to look at the root causes of why parents behave in this way," he said, adding that government needs to ensure that healthy eating programmes are targeted at the right people.

The increase in single-person households and split families was prompting the launch of more 'convenience' foods as well as an increased emphasis on snacking, the study revealed.