I did it once! I will share my experience. It was a nice summer week of mid July 1999. I just quit my well paid job for a large corporation filled with unfriendly people, a month before, and became a self-employed consultant. The previous week a friend of mine insisted on lending me a Dr. Kwasniewski's book "Optimal Diet", forcing me to read it by reminding me with every day emails and almost daily phonecalls. I hated it. I read it and decided to prove my friend wrong by attempting to eat this way for a short time like a couple of weeks, and telling him how my health deteriorated, then stopping it.
I begun one morning by frying myself a scrambled eggs on double slices of bacon. The first scrambled eggs and the first bacon perhaps since 1988 or so. Bacon tasted too salty, eggs tasted tasteless, I didn't enjoy it. I was used to eating a slice or 2 of sourdough brown bread with a nanometer thick monomolecular layer of flora margarine and a jam.
I fully expected my mild transitional chest pain of "unknown" origin that I experienced since around 1996 (until 2001) to get worse, I expected my sporadic once-a-month episodes of tachycardia (had all my life, more frequent after 1996, gone by 2001) but to become less sporadic. I expected my daily afternoon symptoms of hypoglycemia tiredness, shakiness mental fuziness and stress-outedness (since mid 1990-ties until 1999) to get worse and I did not expect at all my painful dry eyes symptoms (had it from around 1991 until 2000) requiring daily eye drops, to change.
Well, I didn't die! Perhaps if I added some buttered lobster...

Best regards ,
Heretic
P.S.
I realize the tone of my story may seem a bit odd. I have to add this to explain why: ever since my out of body/near-death experience in 1979 I do not react on threats like others, and I do not treat most intellectual beliefs and theories very seriously. I also do not have a fear of death!