The Guardian reports that the woman, from Govan in Glasgow, said she was "too scared" to leave her house and did not have anyone to shop for her.
But Salvation Army volunteers and housing officers, who were knocking on doors to check up on people as part of a local Covid-19 food support scheme, gave her hot soup and a food parcel after the discovery in late March.
The newspaper reports that the case reflects soaring levels of food insecurity in the UK as low-income households struggle with reduced income because of furloughs, job losses and extra living costs associated with the pandemic.
The Salvation Army said that, across the UK, it saw an average 63 per cent increase in households receiving food parcels from its 665 UK centres between February and April. It warned the coronavirus pandemic had pushed the nation to a "poverty tipping point."
The Glasgow woman, who lived on the top floor of a tenement block, was discovered on March 23rd by a mobile food support project of the Salvation Army, a Christian Church and charity, and by Govan housing association.
Tracy Bearcroft, a major in the Govan Salvation Army, told the Guardian she had "no one to get anything for her" and was "too frightened to go out," adding: "At first it was very scary for a lot of old folk, who didn't want to go out because they thought they would catch (Covid-19) immediately and have to go to hospital."
Bearcroft, who runs the army's Govan mobile food project with her husband Mark, said demand had risen 10-fold in recent weeks.
The Govan area, where many are on low-paid or zero hours contracts, has been badly hit by Covid-19.