NHS hospitals in England are hiding patient dissatisfaction with the food they serve, campaigners say.
The Campaign for Better Hospital Food said NHS Trusts routinely rated their own food highly.
But patient surveys showed nearly half of people were dissatisfied with what they were offered to eat.
The campaigners want mandatory standards introduced for hospital food, like those which already exist for prisons and schools.
In the past, NHS staff in England have carried out annual assessments of the quality of hospital food.
In 2011 they rated nearly 98% of meals as "good" or "excellent".
The inspection system is now changing, but the Campaign for Better Hospital Food points to a survey of more than 64,000 patients carried out by the regulator, the Care Quality Commission, earlier this year.
In that survey just 55% of patients said the food they had been served was "good".
Alex Jackson, co-ordinator of the Campaign for Better Hospital Food, said existing policies that regulate food served in prisons and schools should be extended to hospitals.
"It is time for the government to come clean about the sorry state of hospital food in England and set mandatory standards for patient meals.
"This would only involve extending an existing policy which has seen it set mandatory standards for prison food and food served in government departments, to go alongside those that already exist for school food.
"Surely patients recovering in hospital have the same right to good food as government ministers, school kids and prisoners?"
Campaigners point to hospitals such as Darlington Memorial, where the award-winning food is locally sourced and cooked on site.
Through buying in bulk and cutting down on waste, the hospital manages to stick to a very tight budget of around £2.60 per patient per day.
Patient Concern called the findings "shocking".
It called for protected cash for hospitals to be spent on better meals.
Roger Goss, co-director of Patient Concern, said: "If managements are deliberately misleading us on hospital food, on what else are we being misled? Patient safety? Quality of care?"
In a statement, a spokesman for the Department of Health in England said there were many examples of good food across the NHS.
"But we recognise that there is too much variation across the country - that is why we have implemented a tough new inspection programme.
"We support the principle of food standards but do not think that legislation is the right way to proceed.
"We believe that the best decisions on hospital food are those taken locally by chefs and catering managers."