More than one tonne of hospital meals are going straight in the bin every year at the St Helens and Knowsley Teaching Hospitals NHS Trust, figures show.
According to NHS data, the trust recorded 19kg of unserved food going to waste over one seven-day period in March 2018 - the equivalent of 1 tonne every year.
The figure covers just the excess meals left on the trolley at the end of a meal service, and does not include food that patients leave on their plates when they have finished eating.
It includes starters, main meals and desserts during lunch and dinner, but does not include breakfast.
The Government has announced a 10-year plan for the NHS, which includes a commitment to tackle waste.
However, more than 7,130 tonnes worth of meals are currently going in the bin across the NHS in England every year, the data suggests.
Food waste is a "big problem" in the NHS, according to the food and farming charity Soil Association, which campaigns for better food in hospitals.
Rob Percival, policy officer at the Soil Association, said it is often linked to the method NHS trusts use for catering services.
Many rely on pre-prepared meals that are delivered to sites which may not have the freezer capacity to keep any surplus, he explained.
"Trusts should be investing in fresh preparation of meals as opposed to bulk purchasing, which gives catering staff a greater degree of control," he said.
"Then you won't be dealing with the scenario where you have 1,000 plated meals delivered but you only have 300 orders from patients and the rest goes in the bin."
Maisie Borrows, research manager at the Reform think tank, said: "These figures are just the tip of the iceberg and highlight the need for reform.
"All NHS hospitals should strive to be as efficient as the ‘best-in-class’, looking at improving efficiency by harnessing technology and insight from data.”
The NHS Digital figures reveal that the trust spent £2.5 million on food services in the 12 months to March, including labour, delivery and management costs.
During this time, there were 821,155 meals requested by patients.
This would give an average cost of £9.22 per patient for a three-meal day, if no meals were wasted, compared to an England-wide average of £12.59.
According to Mr Percival, the quality of hospital meals could also contribute to a higher degree of waste as patients are more likely to leave leftovers.
He has urged trusts across the country to focus on offering appetising and nutritious meals using high-quality ingredients.
He said: "Adequate nutrition is important for a patient’s recovery and a huge amount of plate waste is generated because food is of a low quality - ready-made, reheatable meals that are highly unappetising.
"It sends a pretty disappointing message about the importance of food to health.
"If the NHS is supposed to be the beacon of health, they should be modelling this."
A spokeswoman for NHS Improvement said: “While there will be legitimate reasons why NHS trusts spend different amounts on food, ensuring that all patients receive high-quality meals is the priority.
“We have recently launched a Healthcare Food Standards Strategy group to support trusts and drive improvement.”