Scientists have investigated a few highly publicized cases of people who claim not to eat or drink for years, yet remain quite healthy. Any scientific investigations that have supported these claims, however, have remained controversial.

It has long been held in Buddhist tradition that those who leave society to meditate and cultivate in the mountains may be able to survive without food and water. Their bodies are said to enter a different state, and since the need to eat would prevent them from concentrating on extended meditation, they are supernaturally able to overcome this need.

The human body is usually said to survive only a few days without water, and only as many as 30 to 40 days without any food. Some people who have been inspired by these claims of continuous, extended fasting have tried it themselves and endured great injury and even died as a result. 

Ram Bahadur Bomjon, a Young Buddhist

In 2005 a young Nepalese Buddhist, Ram Bahadur Bomjon, reportedly meditated for eight months without food or water, separated from any outside contact by a fence. A Discovery Channel crew filmed him for four days and nights straight to confirm that for this period of time he did not have any external sustenance, as shown in the special, "The Boy With Divine Powers.”

"After 96 hours of filming, Ram has defied modern science by continuing his meditation and remaining alive,” the documentary claimed. If it was a hoax, the documentary makers said, it was a very elaborate and skillfully executed one.

Some told Discovery Channel that fasting of this kind is usually hidden from the public, and is part of esoteric spiritual practices.
Hira Ratan Manek, Sun Gazer

Hira Ratan Manek of India is a retired Indian mechanical engineer who started to revive an ancient tradition of sun-gazing in the 1990s. He claims that, since 1995, he has lived off the sun’s energy, which he imbibes by gazing at the sun as it rises and sets, only occasionally drinking tea, coffee, and buttermilk.

Rumors that NASA studied Manek and confirmed his amazing ability have stirred up controversy around him. Manek told Dr. Mercola, who wrote about sun gazing on his blog: "The media sometimes reports things in haste, I have never said anything about NASA. Those who believe, they do it, and those who do not believe—to them, any amount of explanation won’t work.”
"Those who believe, they do it, and those who do not believe—to them, any amount of explanation won’t work.”
— Hira Ratan Manek

Indian Neurologist Dr. Sudhir Shah has expressed enthusiastic support for Manek, vouching for the genuine nature of his permanent fast.

In the 2011 documentary "Eat The Sun,” directed by Peter Sorcher, Manek is said to be a fraud. Manek was photographed with solid food, the documentary claims, though Manek said he was just posing for a picture with it. The documentary shows a letter said to be written by Manek in which he apologizes for lying about not eating. Manek has not, however, made such an admission anywhere else.
Optometrist B. Ralph Chou warns against the hazards of sun-gazing.

Optometrist B. Ralph Chou warns against the hazards of sun-gazing in an article on the NASA website: "The only time that the Sun can be viewed safely with the naked eye is during a total eclipse, when the moon completely covers the disk of the sun. … Even when 99 percent of the Sun’s surface (the photosphere) is obscured during the partial phases of a solar eclipse, the remaining crescent Sun is still intense enough to cause a retinal burn, even though illumination levels are comparable to twilight.”
Prahlad Jani, Indian Yogi

Dr. Shah has similarly endorsed Prahlad Jani, a yogi who claims freedom from the usual demands of the human body. From April 22 to May 6, 2010, Shah and a team of researchers said they kept Jani under constant surveillance and that Jani did not eat or drink during this time.

The research was publicized through an India TV broadcast. Sanal Edamaruku, author and president of Indian Rationalist Association, decried the research as deficient. In an article for The Guardian, he wrote about some loopholes he observed: "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.”
Michael Werner, a Western Chemist

It isn’t only Eastern spiritual cultivators who have claimed sustenance without food. Dr. Michael Werner has practiced sungazing and claims he has lived years without food. The official synopsis of his book, "Life from Light: Is It Possible to Live Without Food? A Scientist Reports on His Experiences,” states: "Michael Werner presents a new type of challenge to skeptics. A fit family man in his 50s, he has a doctorate in chemistry and is the managing director of a research institute in Switzerland. In this remarkable account he describes how he stopped eating in 2001 and has survived perfectly well without food ever since. In fact, he claims never to have felt better! Unlike the people who have achieved this feat in the past, he is an ordinary man who lives a full and active life.”

Could Melatonin Have Something to Do With It?

The blog Q4LT speculates that melatonin—a hormone found in the human body related to sleep cycles and metabolism—may have something to do with the ability to survive without food. Q4LT investigates a variety of issues related to the pineal gland in the brain, melatonin production, and more. A Q4LT article titled, "Making a Case for the ‘Impossible,'” points out that melatonin is key in regulating adenosine triphosphate (ATP).

ATP is fundamental in storing and releasing energy in our cells. Q4LT cites several scientific studies conducted over the past several years that show melatonin can normalize ATP production. The pineal gland in the brain produces melatonin. The pineal gland has also been identified in Eastern spiritual traditions as the seat of human consciousness, as a key physiological link to a person’s spirit.

Though it cannot be said that increased melatonin production—perhaps motivated by some effect of meditation on the pineal gland—could allow a person to do completely without food or water for years, it is interesting to speculate that it could have some effect in this regard.