Good vegetarian substitute for tuna fish?

This is the best veggie stuffing for pita that I can think of! http://www.food52.com/recipes/11921_worlds_easiest_falafel_and_tzatziki Its a grea recipe!

Thanks everyone for the input! While I was shopping yesterday I grabbed a can on white beans. I will half mash them and dressing them with the same as the Tuna. I'll serve the grapes on the side. I also made a great quinoa salad with lots of finely chopped veggies.
He's already getting/got tempeh, seitan and tofu this week.
The tuna of the sea recipt looks great!
Will look into getting the 'Appetite for Reduction' book. Great title!
I think I will have to make a jicama slaw for a side for everyone.
Thanks for the suggestions. I love food pickle!

My favorite tuna salad alternative is the chickpea part of the Goddess Nicoise salad in the book Appetite for Reduction by Isa Moskowitz. If you are running a weight loss camp you have got to check out this book. Here is a recap of the recipe I found on a blog. http://reductionproject.blogspot.com/2011/04/goddess-nicoise.html

I second the jicama, once it is squeezed slightly dry it has a similar texture to tuna, and with some chopped sunflower seed mixed in along with traditional things like onion, celery, mayo, you really get the flavor, too.

One last thing I would add (and something I learned from that book) is that a big misconception about vegans is that we don't get enough protein. The thing is that we get our protein from many different sources, not just one, which actually makes protein absorption easier for the body. There is protein in vegetables, legumes, grains, fruits and seeds. That is why it is so important to have variety in your diet-- as a meat-eater or a vegan.

I agree with @eatlovedrink, the Chickpea of the Sea recipe is awesome!!!! Lots of vegetarian recipes for tuna salad use chickpeas as a substitute and it works very well. Good luck and would love to hear back about which recipe you finally decide upon.

I am SO IN LOVE with this faux-tuna recipe called "Chickpea of the Sea" that was created by a yoga retreat in Western Massachusetts (Kripalu). I've been vegetarian for a long time, so my memory's not the best of the real thing, but this tastes just awesome to me. All of my non-veggie friends who've tried it have like it, too. In fact, an old tuna-fish-eating boyfriend used to beg me to make the veggie version. Here's a link to the recipe:
http://www.thekitchn.com/thekitchn/vegetarian-lunch-chickpea-of-the-sea-114022

Enjoy!

I'd second the tempeh and seitan. You could also go with tofu. How about a curried tofu (tempeh/seitan) salad? That would be wonderful stuffed in pita, and it would go nicely with grapes, finely chopped red onion, celery, and cashews or other nuts.

As far as alternates, this is a sandwich I have made for numerous Superbowl parties, I will immediately omit the provolone and mayo for your situation and the focaccia may be a deal breaker with the carbs/sugar but you could cut out the middle part of the bread and get it thin and make it work. This makes 16 sandwiches.

2 loaves focaccia
1 16 oz. container ricotta
10 oz pesto
1 eggplant sliced and roasted
1 jar roasted red peppers, drained and dried
1 jar artichokes drained and sliced thinly
spinach leaves

Combine the ricotta and pesto and spread on both sides of the bread and layer the remaining ingredients.

Faux tunas abound! First I tasted was based on crushed cooked chickpeas, but "Tempuna Salad" from Tempeh Cookery by Coleen Pride (from The Farm, a pioneer in tempeh becoming an American staple) -- should do it.
Combine 8 oz tempeh (steamed 20 minutes, cooled and grated), 1 cup diced celery, 1/4 cup chopped green onions, 1/4 cup pickle relish, 3/4 cup mayo, parsley
Tempeh can be one of those chameleon foods -- with the right dressing you can 'mock' anything, almost.
For more options, the beans Sam describes would be excellent, but the rice isn't necessary -- pita provides the grain (and it doesn't have to be matched at one meal, as long as there is variety). Hummos, refried beans, and other spreads made from beans give you plenty of alternatives. Follow your instincts on the complementary fruits or veggies. They might make better garnishes than components.

As a former vegetarian (23 years of it) my biggest problem with veggie alternate foods was they rarely filled me up. So I would say go with a heavy protein low in fat, seasoned seitan or even egg whites. I like the idea of beans and jicama and quinoa. Could you also add some marcona almonds (or any other nut) with the grapes for bulk? In moderation, of course. Any white bean puree would work well with grapes.

What about seitan went to a picnic yesterday and a guest who is vegan brought a mock chicken salad made with it. Was pretty tasty I guess its not much like tuna more the texture of chicken. Could make a nice vinaigrette, herbs grapes and other veggies. She used vegan mayo, herbs and veggies.

If you're looking for proteins, what about quinoa? That may go nicely with grapes. You can change it up and make it savory or sweet.

Doh. I see you tagged the post protein. For that maybe add some black beans simmered in cumin, with some rice to make a complete protein..along with the jicmaca etc. Olive oil, and lime juice.

I'm not sure how well those elements would work with grapes. Orange slices should work there tho.

Jicama salad might work with grapes, cucumber, red pepper, fresh herbs (maybe mint and basil, and chopped cilantro roots/stems). Adding a citrus element like orange juice or lime would pare well.

Or any vegetarian ideas to stuff in a pita!