Lesley Carter, clinical lead for the charity’s Malnutrition Task Force, said too many people – in particular women – were failing to adjust their diet as they aged.
“We’re seeing this all the time – a lot of women have been dieting on and off all their life, or at least they’ve been very conscious of what they eat, and even as they become elerly they’re still chomping on the salads,” she said.
“Often that’s not the correct diet for someone who is ageing.
“They need to be trying to eat a lot more protein.”
Even two or three days of malnourishment can have serious physical effects for elderly people.
Often the problem is only recognised once a patient has been admitted to hospital.
Age UK says that when an elderly person cannot face a large meal, they should be offered snacks and smaller meals throughout the day.
Dianne Jeffrey, who chairs the task force, said: “It is shocking that 1.3 million older people suffer from or are at risk of malnutrition in our country and the root of the problem doesn’t just lie with poverty.
“There are other contributing factors which add to the risk.
“Public health messages that don’t always relate to this age group; a lack of ability to shop, eat and drink at home without help.
“As well as loneliness and isolation, grief and bereavement, poor physical and mental health or a lack of awareness of the risks by health and social care staff.”