How can he not have eaten, drunk or excreted in over 70 years?

Science examines Chunri wale Mataji

A high-powered team of scientists of the New Delhi-based Defence Institute of Physiology and Allied Sciences (DIPAS) analyses reams of clinical data and readings.
These were taken earlier this month at Ahmedabad’s Sterling Hospital, where Jani agreed to be the subject of a unique 15-day observation study, one backed by cctv monitoring and 24-hour  surveillance to ensure that he did not break his own strict rules.

Earlier,  in November 2003, he was observed for ten days by a team of doctors led by Sudhir V. Shah, an eminent neurophysician keen to decode the science behind fasting and meditation.

Jani’s “no food, no water, no ablutions” claim was found to be genuine then, as it was by DIPAS this time.
Then, as now, a battery of tests had been carried out on him.
“The only condition he set us was that we should not conduct any invasive procedure,” says Dr Shah. “We respected that.”
http://www.outlookindia.com/article.aspx?265459