He was admitted to hospital after eating so much bran on a regular basis that it had set as a solid mass inside his bowel - and had to be cut out by surgeons.
National consumption of bran has shot up over the past decade, largely because of health messages that the dietary fibre may help to prevent bowel cancer, but doctors are now warning that they may have to set a limit on how much people should eat.
"Public awareness is at an all-time high with regard to healthy eating and current advice seems to encourage as much bran as you can palate. But we now have to think whether we should modify the advice," says Ken Shute, consultant surgeon at the Royal Gwent Hospital, Newport, who reports the case of the bran addict in the archives of the Royal College of Surgeons.
After the operation, the patient confessed to doctors that he had become an addict as a result of publicity surrounding bowel disease and the beneficial effects of bran. "He was a well-educated man and he was admitted to the hospital with an acute small-bowel obstruction, and a large amount of solid plant matter was removed. The mass appeared to have formed as a direct result of over-consumption of bran," Mr Shute says.
One of the problems with eating too much bran is that it contains phytobezoars, large conglomerations of vegetable fibres which are probably very useful to some animals but indigestible in man where it can build up and cause obstructions in the bowel.
It is not known how many people have fallen victim to over-eating of the substance, but the likelihood is that in many cases the bowel has managed to cope with the problem.
Mr Shute and his colleagues say that it may now be time for vegetarians and the elderly, considered to be the two groups most at risk, to be given new advice on how much to consume.
"Is it safe to continue with the current philosophy where 'the more the merrier' appears to be the general medical consensus?" he asks.
Nutritionists also point out that fibre can be obtained from a variety of sources, particularly green vegetables and fruit.
Carol Sinclair, author of the IBS starch-free diet, says that there are other disadvantages with bran. "It contains phytic acid which blocks the absorption of calcium, magnesium, iron, zinc, copper and vitamin B6. And because it comes from the outside skin of the grain, usually wheat, it contains a high percentage of the chemicals sprayed on the crop," she says.
The Royal Gwent patient apparently recovered without mishap - but his passion for bran, which was meant to keep him out of hospital rather than put him in, is said to have waned.