The British Association for Parenteral and Enteral Nutrition (Bapen) the condition costs an estimated£13bn a year.
Bapen says malnutrition is a greater problem that in hospitals and care homes - where the focus of government action has generally been.
Bapen's report Combating Malnutrition notes a disproportionate burden of malnutrition in deprived areas which exacerbates health inequalities.
It puts forward 25 actions to reduce both the cost of the condition to the taxpayer and the numbers at risk.
Professor Marinos Elia, chair of the Advisory Group on Malnutrition, said: “Government and the NHS together with the social care, housing and community sectors must now press forward with embedding nutritional care and treatment into daily practice to combat malnutrition where it starts - in the community.”
Bapen's report also calls for 'nutrition czars' in hospitals and care homes.