1) you can become B12 deficient. You may last up to 5 yrs depending on how much is stored in your liver. But don't count on 5 yrs.

2) the amino acids in vegetarian foods are low in methionine and cysteine. Methionine is used in the body to make SAM which is a methyl donor to 3 things:
a) liver health/regeneration
b) joint and tendon repair
c) neurotransmitter synthesis

3) Certain blood types do not do well on vegan diets.
The book Your Body Knows Best goes into that genetic research.
http://www.becomehealthynow.com/arti...nutrition/234/
People with Type A are often most comfortable on a vegan type life style.

4) vegetarians often become depleted in zinc. This is because the phytates in the
vegetables complex zinc and prevent its absorption from the GI tract. Most foods
high in zinc are seafood and meats. (both not included in vegan fare).

It is my opinion that severely restricted diets like this one are not healthy in the long run. We evolved as Omnivores, so our bodies expect certain nutrients to function well.
Ovo-Lacto vegetarians often do better than vegans.
And eliminating fish? That is the worst of all! JMO.

Going gluten free is a good idea. You will see what works for you that way.
Many people are gluten intolerant today (I suspect NSAIDs for causing that)

This restrictive diet is similar to the Cell Program by Dr. Jensen-Kittley. She uses a similar
elimination diet early in her program to detoxify and identify things people react to. Once people identify what is bothering them, they can return to other foods in moderation.
One thing I learned from reading her was that the nightshade family and Lily family are hard for ME.

Her program is very interesting-- check it out:
www.obesitysanswer.com

And depending on your age--- you may have to invest in Beano!

edit to add... the typical deficiencies I list here are slow to develop...you do not see them
immediately. But with time low zinc== hair falls out, immunity goes down, poor protein== hair loss, and low B12 leads to neuro damage slowly.

One has to make sure you are getting enough Omega-3s from this diet as well. Dr. Ornish made this mistake on his drastic cardio diet which is similar to this one, and when his patients started to die
he added Flaxoil supplements.