Beer and her foundation regularly receive letters and emails from "helpless and disappointed" residents and their families, pleading for help to get better food in their aged care home.

"It just breaks your heart because it doesn't have to be like that. It should never be like that," Beer told the aged care royal commission this week.

Nutritionist Sandra Iuliano finds it sad that many residents have to rely on family members bringing in food to get the nutrition they need.

The food provided in residential aged care is inadequate, she said.

"Basically these residents are malnourished and they're starving to death."

Access to adequate food is a human right and not a privilege, the Dietitians Association of Australia told the inquiry.

Its CEO Robert Hunt described cases of aged care residents being mistreated and abused as tragic.

"But for years and years and years this silent, faceless abuser called malnutrition has been around."

Dietitian Sharon Lawrence said research showed anywhere from one-in-two to two-in-three aged care residents are malnourished.

About 1.14 million older Australians living in the community are at risk of malnutrition and another 304,000 are actually malnourished, she said.

Chef Timothy Deverell recalled seeing signs on residents' doors at one facility with requests like 'please give mum an extra dessert, she is losing weight'.

Mr Deverell said there is a substantial gap from top to bottom in the quality of food in residential aged care facilities, and unfortunately the majority are at the bottom.

Places with food budgets of $14-$17 per resident per day can offer better quality meat and vegetables, decent portion sizes and a variety similar to a cafe or restaurant.

One facility with a $16 budget serves filet mignon, salt-and-pepper squid and seafood baskets.

Chefs told the royal commission about being limited to $6.50 or $7 budgets, mainly through outside caterers but also within aged care facilities.

"I have been told by other chefs that some operators work with $3.40 per resident per day," Mr Deverell said.

He described the quality of produce at some aged care facilities as appalling.

"I regularly was told by management to use food that was clearly past its use-by date or had spoiled."

Mr Deverell said a number of facilities recycle leftover food returned to the kitchen and turn it into texture-modified meals, for people who have difficulty chewing and swallowing, for the next day.

Maggot-infested rubbish was stored between serving trolleys at one "quite upmarket" facility, where the cool room was full of rotten produce and meat that had turned green.

The royal commissioners heard about residents being fed unpalatable "slop", cooked meals being cold by the time it reached them, repetitive menus, lack of choice and inflexible meal times.

Chef Nicholas Hall said some aged care providers and third-party caterers talked about food satisfaction but were really focused on saving money.

"They're just racing to the bottom to see who can feed for the lowest amount of cost."

Mr Hall described having to cut corners by using frozen and processed foods on a $7 a day budget.

"At the end of the meal if the resident was still hungry and they wanted more food, there was no more food to give them."

An Australian study put the average daily food expenditure in residential aged care in 2016 at $6.08 per resident, which Dr Iuliano noted was less than the $8.25 spent in prisons and the $17.25 spent by older adults in the community.

Dr Iuliano and Ms Lawrence said a $6 budget will not meet residents' nutritional needs.

"There's no chance that we could meet the overall nutrition requirements of a healthy person, let alone a frail, older person whose nutrient needs are even more extensive than a healthy older person," Ms Lawrence said.

Beer wants the food in aged care homes to be full of flavour, goodness and pleasure - something not possible on a $7 budget.

"It's just impossible," she said.

Beer recalled one cook in a Maggie Beer Foundation masterclass came from a far north Queensland aged care home with a budget of $4.50, "which is a disgrace".

She said the minimum would be $10.50, "when every single thing is right" such as having a vegetable garden.

But for $14 a day, Beer said, you can do really good food and make residents very happy.

The 74-year-old wants the smells of home cooking to permeate aged care facilities and the food to have the right flavour and ingredients.

She said even the large percentage of food cooked, chilled and brought in from outside could be enhanced in a facility's satellite kitchen by adding the enticing smell of bacon or onions being cooked in butter.

"If a resident is not seduced by the food, they're not getting any nutrition because they don't want to eat it."

Dr Iuliano agreed both the nutritional intake and the whole eating experience need to be improved.

"We forget a meal should be enjoyable. It shouldn't be just nutrition shoved into the mouth, and that's often the case because there's not enough time to do it.

"What we are failing to remember is that food is important to them. When we make that food tasty and nutritious and meaningful to them, they will eat it.

"And if they eat it, they stay nourished."

Australian Associated Press