When John Maffioli first fell ill at 19, he put it down to the excesses of his life as a university student. But after six months of acute stomach cramps he had lost almost two stone and was suffering extreme fatigue.
He was diagnosed with Crohn's disease, where the body's immune system attacks the digestive tract, causing damage and inflammation.
And he feared the debilitating gut condition would mean a lifetime of medication and even surgery, with an increased risk of cancer.
Remarkably, eight years after his diagnosis, John, who is one of 60,000 Crohn's sufferers in the UK, is free of symptoms - yet has never had a single drug treatment.
He has run the New York Marathon, regularly plays club rugby, and achieved this medical breakthrough thanks to a simple diet.
John, a 28-year-old accountant, is one of about 1,000 patients who have taken part in a continuing medical trial at Addenbrooke's Hospital, Cambridge.
Problems had started during his first year studying geography at Nottingham. 'I was experiencing terrible stomach cramps, not unlike food poisoning, and on a bad day going to the toilet up to ten times.
'When I started university I was 12st,' he says. 'But by my second year I weighed around 10st, and looked pretty skinny at 5ft 8in. I was pale, tired all the time and had dark circles under my eyes.'
John was diagnosed with Crohn's disease after a colonoscopy and blood tests. The illness most commonly begins between the ages of 15 and 25.
Periods of remission do occur but flare-ups produce stomach cramps, nausea and severe digestive problems.
The first line of defence for most adult sufferers is usually powerful antibiotics to battle infection, drugs which reduce inflammation,
and immune-suppressant medication. These are drugs which carry a host of side effects such as weight gain, mood disorders,
serious infections and an increased risk of cancer of the lymph glands. But at Addenbrooke's Hospital, gastroenterologist Professor John Hunter
and his team identify foods that act as a 'trigger' for symptoms, eliminate them from a patient's diet and 'switch off' the disease. Now 90 per cent of his
patients are symptom-free and 56 per cent can resume a normal diet after five years. During the first phase of treatment, patients consume only
specially formulated drinks. 'They contain all the nutrients a patient needs, already broken down into their most simple constituent elements so the
body does not have to do any work digesting them,' explains Professor Hunter. 'By taking the gut out of action, we effectively switch off the disease.
After two to three weeks, 90 per cent of patients find their symptoms have disappeared.