After talking today about metabolism and the twinkie diet that Professor Mark Haub went on, I did some research and found a guy that actually didn't eat for 1 year and 17 days in order to lose weight. He ended up losing 275 lbs and went from from 456 to 181!
In 1965 in Scotland, the anonymous man went to the hospital at Dundee and told the doctors his plan and, despite the doctors advising against it, he went through with it and had the doctors monitor him throughout. He was only fed yeast, multivitamins, and potassium tablets over the time period. He also only defecated every 40 to 50 days.
Article on it
Unfortunately the event was not scientifically documented so I couldn't find any official information on it beyond random articles online. Even though some of the specific details are different throughout different articles the general story is the same, and there are also multiple other accounts of people doing something similar.
Interesting AMA on Reddit of a man that went through this
There are also (as expected) a large number of health risks that go along with this. The man who posted on reddit most likely has kidney disease, an unstable heart rate, and has had to undergo multiple surgeries. There are also others who have attempted starvation and have died from heart failure, small bowel obstruction, and lactic acidosis from refeeding after the fast.
Even though starving has worked for a couple people, it is still extremely dangerous and is likely to cause death. However it is pretty incredible to see people that have survived this to act as a testament for what the human body is capable of.