A study was conducted on a yogi who claimed that he had not eaten for 70 years. The study was done for 15 days. But its results were not available in any paper as per search on Google Scholar.
Yogi - Prahlad Jani
Year 2010
http://www.naturalnews.com/029716_fasting_health.html
http://drdo.gov.in/drdo/whatsnew/DIPAS-UPDATE.pdf
http://www.sudhirneuro.org/files/press_release.pdf
Even though the doctors and scientists wanted to confirm the phenomenon first and then explain it, so far we have not seen any explanation.
http://abcnews.go.com/Nightline/gurus-mystics-india-performing-miracles-magic-tricks/story?id=11929407#.UIfflm_Mgro
October 2010