The study, commissioned by Age Concern and Help the Aged Scotland, found more than a third of older people admitted to hospital rated the food as "poor" and 16 per cent had their food or drink left out of reach.
It also found that while many patients did not need help with their meals, 57 per cent of those who did, did not receive it.
Age Concern Scotland parliamentary officer Nick Waugh, who compiled the report, said: "It gives a clear indication that problems indicated in the past are still persisting despite the efforts of the NHS and Scottish Government."
"There seems to be a disconnect between intentions and the practice on the ward."
Malnutrition has been identified as a major public health problem in the UK, with between 15 per cent and 40 per cent of hospital admissions affected, and more than two million adults underfed in Britain.
Experts say that being malnourished reduces older people's mobility as well as their ability to fight infection and shrug off illness.
The report states: "These issues are significant in their own right, but are compounded by the fact that as many as 40 per cent of older people admitted to hospital have malnutrition on arrival.
"As a result, some 60 per cent of older hospital patients are at risk of becoming malnourished, or more malnourished, during their stay in hospital.
"Malnutrition has a serious impact on recovery times and post-operative complications, and increases the likelihood of future re-admissions."
As part of Age Concern Scotland's Hungry to be Heard campaign, more than 100 older people who had recently been in hospital were asked a series of questions to ascertain whether the standards for nutritional care in acute hospitals were being met.
Some 47 per cent rated the food as "good" or "very good" but only 45 per cent were weighed on admission, despite concerns about malnutrition and a government standard that states patients have to be assessed and screened.
The report states: "It does strongly suggest that there is a distinct problem for many patients who need help to eat their food.
"In addition, 16 per cent of respondents reported that they were not given sufficient time to eat their meals.
"Our survey shows that 16 per cent of respondents had a meal or drink left out of their reach on at least one occasion – something that is unacceptable and in many ways represents one of the most significant failures to implement the standards relating to nutritional care.
"It undermines the implementation of all the standards as hospitals only counter their good work by leaving it out of reach of patients."
The report concludes that further research should be conducted by the Scottish Government as standards are not being fully enforced.