Good question, John.  I think it depends partly on how you go about it
and partly on the strength of your motivation.

I took an 11-day fast about 4 months before I started an all-raw diet,
which I shifted to immediately as soon as I became philosphically
convinced of its superiority.  For me, whose prior diet was nowhere near
as bad as you cite (it was more macrobiotic-like), the first 5 months
were very rough indeed.  I felt and looked awful.  But I hung in there
and am glad I did.

On the other hand, I have a friend whose diet was nearly as bad as you
mention, but who fasted for 17 days immediately prior to going on the raw
food diet, and she experienced no difficulties.  So I think a nice long
fast of 2-3 weeks to clean yourself out and to normalize your digestive
organs would probably make the transition a piece of cake (er, uh,
cantaloupe) for you and as quick as possible.

If you can't fast and don't have the stomach for going cold turkey (er,
uh, cool watermelon) on cooked food as I did, it might take you a couple
years or so of gradually eliminating the bad and bringing in the good.
But I don't know of any painless transitions.  It's hard to violate the
Laws of Life for decades and not expect to pay the piper with various
withdrawal symptoms and cleansing reactions along the way.

Best of luck.

Bob Avery ([log in to unmask])