the vegetables have beta-carotene, which is a sort of precursor of
vitamin A.  beta-carotene is not as toxic as vitamin A.  But don't eat
the same ones every day; you should get some crucifera vegetables
(cabbage, brussels sprouts, cauliflower, broccoli) among others.

Sue(tm)
Lead me not into temptation... I can find it myself!

Even with 4 or 5 veggies you can have variety, especially if they are
from different families--i.e., cabbage and broccoli would give less
variety than broccoli and tomatoes.  A friend ate several carrots every
single day without fail for months and her skin turned yellow.  Other
strange symptoms appeared, she went to the doc, who diagnosed vitamin A
overdose.  His prescription was, stop eating so many carrots.

I doubt there is a real answer to "which would be the healthiest."

-aem

No risk.. not even if you juice them and consume that at 5x
the volume..get a book on raw juicing therapy. or search those
key words on google

If so, how do you recommend I change my

You've said any thoughts would be appreciated so here goes.  I'm no
expert in science and nutrition but have thought about your questions
before from the standpoint of a cook.

For the 5 vegetables each day, I'd try to get one from each of the
following categories:

1) Something in the cabbage family.  That could be broccoli, cabbage,
kale, collards, cauliflower, etc.

2) Something dark orange with beta carotene in it like carrots, sweet
pototaoes, rutabaga (also in the cabbage family), etc.

3) Dark leafy greens including spinach, kale, arugula, parsley or chard.

4) A squash like butternut, acorn, buttercup (also in category #2), or
zucchini.

5) A flavor punch like tomatoes or mushrooms.

I'm assuming that your question doesn't mean that you intend to eat ONLY
vegetables and not get grains, beans, eggs, dairy, etc.  If that were
the case, I'd suggest more in the way of something with calories.  That
leads to my thoughts on your second question.  If you're getting plenty
of other foods besides the 5 vegetables, it is unlikely that you'd get
so much of any one of them that you'd be at risk for an overdose.  You'd
be getting calories from other sources.  If you were trying to limit
your total foods to the vegetables on the list and not eat anything
else, then a vitamin overdose wouldn't be the worst of your worries, but
I suppose it could happen.

--Lia

Just for the heck of it, I asked my optimization routine which 5
fresh vegetables by themselves (i.e. eat nothing else) give the best
balanced diet as measured by NAS RDA's: the answer is corn, onion,
parsnip, sweet potato and winter squash.

If you want nutrients per calorie, nothing comes close to spinach.

Do you consider beans to be a veg? Botanically, they are.
(Of course, to us tomato is a fruit.)

For a few other number-based views of nutrition, see
http://sankey.ws/miscellanea.html

Thanks for all your thoughtful suggestions.. and to anyone yet to
respond, I neglected to mention that I am a 39-yr-old male
lacto-vegetarian in good health who eats a well-balanced diet
including plenty of fresh fruit, whole grains, and very few processed
or sugary foods (no colas, etc.).

chris