The crimson-clad old man with the nose ring tries to tell us that he hasn't eaten or drunk anything since the goddess Ambaji touched his tongue with her finger. That must have been around the time of the outbreak of the second world war.

As there are few things so well established as the biological law no human (and no animal) can survive without the regular intake of food and water, it may be sensible to approach his claim with a degree of scepticism. It is not usually very difficult to expose such characters; I have done it in several cases. But Prahlad Jani has some influential protectors.

Dr Sudhir Shah, neurologist and head of Ahmedabad's Sterling hospital, propelled the silly story of Prahlad Jani into the limelight. In a sensational "scientific" research project, he and his team subjected him between 22 April and 6 May to observation and medical scrutiny. This project is financed and supervised by the Indian defence institute of physiology and allied sciences (Dipas), a wing of the defence research and development organisation. The public figurehead of the study is Dipas director Govindasamy Ilavazhagan, who seems to share Shah's enthusiasm for the case. Jointly, the gentlemen were reported to have confirmed that Jani did not eat a crumb and – more crucially – did not drink a single drop of water during his 15 days under observation – which seems completely impossible. Can scientists be so gullible as to salute a man who claims to turn the basic laws of biology upside down? Did they close their eyes (and the non-stop CCTV camera) when Jani quenched his thirst? There is no doubt that the "total surveillance" had loopholes and the "great scientific test" was a farce.

While the test was running, I exposed some of those loopholes in a live programme on India TV: an official video clip revealed that Jani would sometimes move out of the CCTV camera's field of view; he was allowed to receive devotees and could even leave the sealed test room for a sun bath; his regular gargling and bathing activities were not sufficiently monitored and so on. I demanded an opportunity to check the test set-up with an independent team of rationalist experts. There was no immediate reaction from Ahmadabad. But a sudden call from Sterling hospital invited me – live on TV – to join the test the next day itself.

Early morning, ready to fly to Gujarat, we were informed that we had to wait for the permission of the "top boss" of the project. Needless to say: this permission never came.

Similarly, we were unable to attend Shah's first Jani test in November 2003 (that was financed by Dipas too). Shah has a long record of conducting these studies, which up till now have never been discussed in any scientific journal. They merely try to prove his strange sunshine theory: that humans can stop eating and drinking and switch to "other energy sources, sunlight being one". Prahlad Jani is not Shah's first poster child. In 2000/2001, he tested one Hira Manek for more than a year and confirmed his claim that he was feeding on sunshine only (and sometimes a little water). The idea that Shah's research was investigated by Nasa and the University of Pennsylvania was officially denied by both the misrepresented parties.

Shah is a deeply religious Jain. As the president of the Indian Jain Doctors' Federation (JDF), he proposes that via research, the still imperfect science of medicine is to be brought in line with the Jainist '"super-science" as revealed by the omniscient Lord Mahavir. We can only wonder whether his researcher eyes are sometimes clouded by religious zeal. Interestingly, many members of his team are Jains and his partner in the Manek test was a former president of JDF too.

Shah has also suggested this phenomenon might have potential "military use". And – what a shame! – the Indian defence ministry took the bait. Can they really be so naive as to consider putting the army on sunshine diet? We are trying to find out.