Subject says it all. I'm wondering (even theoretically) if it is possible to decrease consumption of starchy carbs and increase consumption of proteins all without eating fish, meat, chicken, or other animal sources. Eggs are allowed, but nothing that has "lived" can be ingested.
Lost cause or simply a higher level of difficulty?
I do not think it is impossible, but as you had mentioned, you will be approaching the upper limits of difficulty EXTREMELY quickly as soon as you start.
Most who follow a Paleo/Primal way of life subscribe to the idea that their main source of energy should come from fat, specifically animal fat. That would be EXTREMELY hard to do as a vegetarian.
Although, if you allow eggs, it would make it one notch less in the difficulty scale.
I'd imagine that your diet would consist primarily of Eggs, Coconut, Nuts, Avocado, Green Leafy Veggies of all sorts, Peppers, asparagus and so on..
Would you be allowed to have fish oil to help balance out all the omega6s you'd be ingesting? If not, continuing on the Paleo/Primal lifestyle may not be conducive for the long term. You'd definitely see quick results in body composition if you are coming from a SAD or variation thereof..
I was playing around with Nutrition Data and did both a paleo vegan and a paleo pescatarian diet. For a optimal vegan paleo diet coconut products would have to be a staple because other plant fats are too high in omega-6. Some eggs and fish roe for a paleo vegetarian diet would definitely make it better. Either way, these diets require a lot of motivation and the vegan one would require DHA and b-12 supplementation at least.
I don't think it is possible.
Melissa Byers has an interesting blog post about the topic. She gives Paleo nutrition advise to meat eaters and vegetarians/vegans. http://whole9life.com/2010/02/vegetarian/
Given that anthropologists have never found a pre-agricultural people who consume a vegetarian diet, it would seem that a vegetarian diet is by definition not a paleo diet.
I don't think it's possible for vegans, but vegetarian I think it depends on what you will/can eat.
Many vegetarians/vegans get the bulk of their protein from beans, including soy. Beans aren't "acceptable" on primal/paleo, but lots of us make some exceptions. I use dairy, although I limit it. I believe that soy is not "allowed" unless it's fermented? But soy especially is not good for you. In small amounts, it's fine, but large doses is not healthy.
Soy is not at all primal, IMHO as it's only been farmed for about 5000 years....and a good part of that time it wasn't eaten, it was grown, then tilled into the soil, to replenish the soil so other crops would have the needed nutrients in the soil. I don't know how long we've been eating soy, but not very long! If you do have it, it should at least be fermented.
For vegetarians that are willing/able to eat eggs, fish and other animal sources of protein, I think they could do it. But if most or all of the protein comes from plants, I don't think it's going to be easy to get what you need.
Vegetable protein is not as bio-available as animal protein....and without soy, I can't see how eating only eggs for animal protein is going to give you enough of the right amino acids....unless you eat a boatload of eggs!
It's possible to apply Paleo principles to a vegan lifestyle, but I don't think 100% paleo is achievable, but you can get close. I actually did this for almost a year, with the only non-paleo foods consumed being pea protein and rice protein. Zero soy or gluten is necessary. Check out the Thrive Diet by Brendan Brazier and just pick and choose from his recipes (some are paleo, some aren't). Everyday would start with a shake with a protein combo of hemp/pea/rice protein (combine all three). Fats from nuts, avocados, coconut, hemp oils. Except for the morning rice and pea protein no other legumes or grains are consumed. I got very lean doing this. He has great recipes for paleo crackers (really just ground nuts and seeds with coconut oil) that can be used with various dips (I now throw sardines on top). You also don't need the pea/rice protein and use hemp only, I just did (and still do) use it to create a very complete protein (way better than soy).
I think beans and legumes can be consumed if they are prepared by soaking and thorough boiling. Even then, it's nice to keep them in moderation. I'd avoid all the processed protein powders.
However, I think our ancestors didn't eat meat all the time. It seems like hunter gatherers were probably more successful at gathering than hunting. Is that true? If so, then how much or how frequently should we be consuming fish and meat?
Look, hard-core vegetarians already do this by consuming beans. What do you think the Tarahumaras do? They rarely eat meat but regularly eat what they call 3 sisters: corn, beans, and squash.
Today's vegetarians tend to add soy to the mix.
What do you think are McDougall, Fuhrman, Ornish diets? They're plant-based Paleo diets. Matesz joined that camp recently. If you think about it, they're Paleo, too.
In fact, you could make a plausible argument that the Paleo diet is closer to the plant-version than the meat-version. Most indigenous and pre-agriculture tribes ate a starch-heavy diet. Current Paleo is moving towards more starch.
I have been a vegetarian for 22 years and go back and forth between eating fish and taking it out of my diet. At first I was scared to try the paleo diet because I thought it might be too difficult. I found that I love it and have no problems and have had great results. I have been paleo for 3 months. I do eat fish, but I am very conscious about what fish I eat so they are low mercury content and not too much cholesterol. I think it is important to listen to your own body and not make sweeping generalizations about what it god for someone else. My body has never liked meat especially red meat. I get my protein from nuts and seeds, fish and eggs. In the morning I usually have a shake with hemp protein powder and a raw egg with fruit and almond milk, for lunch I eat some type of fish with a yam and greens, and for dinner I usually have lots of veggies, sometimes fish but not always. I track my protein and usually eat a minimum of 60 grams but often as much as 80 to 100 grams because I am still breastfeeding. I find that the paleo diet and the raw vegan diet have a lot in common, because raw vegans have to sprout their grains so grains are limited. I am working on a hybrid of these two diets for myself and thinking of adding quinoa every now and again if I find my body can tolerate it.