The alarming figures have led to fears that thousands of Scotland’s most vulnerable people may not be getting enough nutrition.
Orchard View in Greenock, a 42-bed facility for older people suffering from dementia that was opened last year at a cost of £7million, spent £2.50 per patient each day.
Several other mental hospitals run by Greater Glasgow and Clyde (GGC) health board also spent just a few pounds a day on food and drink last year, including Stobhill (£3.30), Parkhead (£3.40) and Gartnavel Royal (£5.10).
Motherwell’s Airbles Road Centre, a long-stay hospital for older adults and mental health patients, spent £4 per head a day on average in 2017/18.
Mental health patients at the Carseview Centre in Dundee (£7.30 a day) and Bellsdyke Hospital in Larbert (£7.50 a day) are also fed and watered for a minimal outlay.
And Udston Hospital in Hamilton, which provides mental health care for patients over 65, spent £7.60 per head on daily catering last year.
On average, Scottish mental hospitals spent just £11 per patient per day on catering last year – down from a daily average of £12.70 five years ago.
General hospitals spent £13.70 a day on each patient, while long-stay hospitals spent £17.20 a day and community hospitals spent £20.70 a day on average.
Glasgow Royal Infirmary had the lowest catering costs of any general hospital with £7.10 spent per patient per day, followed by Crosshouse in Kilmarnock and Raigmore in Inverness both at £9.70.
Scottish Conservative leader, Ruth Davidson, (L) and Scottish shadow health secretary Miles Briggs (Image: ANDY BUCHANAN/AFP/Getty Images)