When you are ill, your body needs the best possible food to recover.
That is why it is essential that patients in our hospitals should receive wholesome, fresh food.
And what is good for our health is also good for the environment, and good for British farmers.
Back in 2004 I launched a pilot project — led by the Soil Association and Sustain, two environmental organisations — to increase the amount of fresh, local and, where possible, organic food being supplied to London hospitals.
The Royal Brompton and its catering manager Mike Duckett became the leading example of best practice in hospital food.
Four years later we brought Chief Executives from hospital trusts from across the country to see for themselves how it could be done financially and logistically — and to witness the enormous benefits it was bringing to patients by improving recovery rates.
By highlighting a success story, I hoped to encourage others to follow and to recognise why it was so important.
With climate change an urgent priority and obesity costing the NHS £6billion a year, serving good, healthy food has multiple advantages.
Patients benefit from nutritious, tasty menus; British farmers benefit from local, reliable supply contracts and food miles, pollution and greenhouse gases are minimised.
Of course, I was told by some that providing quality food was not a priority, that it is too expensive and impractical.
But by 2009, when I launched the Soil Association's Food for Life Catering Mark at Nottingham City Hospital, the number of hospital trusts becoming beacons of best practice was growing.
This is not just good news for patients. The local economy and local farmers benefit too.
In 2007 I visited a hub of farmers in Kent supplying the Royal Brompton and it is still going strong. According to research by the Soil Association, the story is the same across the country.
There is a thriving organic dairy supplying Darlington Hospital. In Nottingham, a pig farmer was saved from going out of business by winning a contract to supply the local hospital and a Sussex vegetable grower has formed a hub involving many growers to supply some of the county's hospitals.
Contrary to what the doubters said, many hospitals are now proving that it is possible to serve excellent food for no more money than the average cost of a patient's meal in the NHS.
As in everything in life, it is leadership that counts and that is why I was so keen to invite many of these hospital food heroes to Clarence House yesterday, so that I could thank them personally for their efforts.
They deserve our congratulations and praise for showing just what is possible and I am sure their stories will inspire many others in hospitals across the country.