So this is very unscientific reasoning, but anyway: I've done several survival trips, and one of the very first things I learn every time is that conserving (personal) energy is of supreme importance. The necessary tasks involved in staying alive don't use up energy in the same way that a crossfit workout does, but in a survival situation everything you do (including doing nothing) depletes your energy reserves and it all has to be made up somehow. In practice this means that out of your initial energy "budget" must come actions specifically to feed you. What actions you choose to take to feed yourself has a very real relation to whether you live or die over the long term.

In the short term, eating vegetation is nice and easy, using up little of your energy, but it gets you little energy back. It feels initially satisfying, but after about a day, I have to force myself to consume any more vegetation, because just looking at it makes me feel sick. It just doesn't abate the hunger or weakness (although certain plants do actually abate hunger or stimulate energy as part of their medicinal effects). I find the same holds true of mushrooms.

Eating plant roots is satisfying for maybe one or two more days at most. It takes more energy to get them, and often takes some cooking to make them digestible, and they give you some much needed energy. But this is not a lasting boost of energy and after a while this hits the point of diminishing returns as well, and my body makes me not want to eat any of it.

The most energetically expensive food to get is animal food (although collecting certain shellfish and seafood items can be pretty easy). It's also often dangerous (especially in a survival situation) whether you're making impromptu weapons or setting up traps. However, on day three of any survival trip, it is pretty much the only wild food source which remains desirable. One tiny little snail has meant more to me than five pounds of leaves and stalks or roots and berries. I've been on trips with other people where we have actually shared a snail between us, and it was still more satisfying than all the plant foods we had collected.

Now hunting and trapping - especially with primitive and improvised tools - is very tiring and very much a gamble. It seems to me that if it were possible to healthfully feed yourself from nothing but plants, then that would have been the most successful strategy in our evolutionary history. If it were possible to be a healthy vegan, we should see virtually every pre-agricultural tribe being vegan. Instead, what we actually see, to the best of my knowledge, is that none of them were. Because of this, I cannot but believe that it is not possible to be a healthy vegan.

Short answer: Unlikely.

I think Patrik is right. It is unlikely. I do think it is possible, but it depends on what you mean by "healthy." Are you talking "better than average?" or "Optimal?" [Edit: Also, to make a long story short: I think a more interesting question is not whether it is possible for a vegan to be very healthy -- of course! -- but rather whether a large group of vegans will be healthy relative to the SAD (yes) or relative to Paleo (I don't think so).]

There are genetic freaks out there. Some of them can eat nothing but rancid Doritos and Diet Coke, smoke unfiltered cigarettes, watch soap operas all day, and still live to be 100 years old. Some of them can walk into the gym after being sedentary for a few months and still lift more weight, run faster and longer, jump higher than you can.

These people will outlive and outperform many of us, even those of us who work pretty hard at it.

That doesn't mean that their diet or lifestyle or training regimen is optimal.

Perhaps if these freaks switched to a Paleo-ish diet, they would live even longer and experience an even higher quality of life. Maybe they would become even better at their sport. Maybe their sex lives would get better, they'd be happier, their energy levels would be higher. Who knows.

Ultimately, it is pretty hard to prove what is "optimal". It also probably depends on your definition of optimal (do you want to favor athletic performance, or longevity and long-term health?). Any self-evaluation of your diet and lifestyle choices is necessarily subjective and prone to distortion.

Vegans can have have reasonable or even excellent health outcomes, whether they follow (what we would consider) healthy diets or not -- at the individual level.

You also need to consider what "vegan" really means. Vegan diets can range from wheat + soybean + soybean oil, to soaked/sprouted lentils, no wheat, coconut oil only. You can bet the farm that there will be a LARGE difference in health outcomes there.

Now, at the group level, take hardcore 1000 vegans vs. 1000 hardcore Paleo/Primal eaters and let's compare health outcomes over the next 50-75 years.

To be fair, let's assume the vegans all supplement B12, zinc, omega-3 algae oil, etc. religiously and get lots of sunlight. (I don't know all the main things that vegans need to supplement, but you get the idea.) They eat local organic produce. They soak, sprout, ferment, grind their beans and lentils, and avoid wheat. They cook everything in organic, unrefined coconut oil, avoiding vegetable oils of all kinds. The only stipulation is that they eat no fish, no meat, no animal products whatsoever. Honey is fine.

Let's also assume the Paleo group eats exclusively grass-fed meats and lots of fresh, healthy seafood, eats local organic produce, supplements anything necessary, etc. etc. etc.

Basically, let's compare the healthiest possible vegan diet to the healthiest possible Paleo diet.

My money is still on the Paleo group in terms of longevity, quality of life, and health outcomes. I can't prove it in a court of law, but I think the observational evidence is suggestive, from studies of ethnic and religious groups that are mostly vegetarian or ostensibly vegan, compared to studies of hunter-gatherer groups.

I do think the vegan group would still have improved health outcomes vs. a control SAD group.

This is the wrong question. Is it possible for otherwise-healthy adult individuals to be vegan and healthy? Numerous scientific studies support that with proper supplementation it probably is. I have a relative who has been vegan for 30 years and is just as healthy as my other relatives.

Where it's murkier is:

• Whether it's possible for unsupplemented vegans to be healthy (probably not according to most research)
• Whether this diet works for everyone
• Whether this diet is appropriate across generations

What I'd suggest to vegans is

• Take your b-12, DHA, retinol, and taurine supplements
• Don't be afraid of fat
• Consider not having children. The environmental impact and total net animals killed is greater from having children that from eating meat and the diet isn't really proved in that area.

Why would you take supplements instead of eating tasty food?

Perhaps off topic but.... diets designed for athletes- in this case body builders- are NOT a healthy diet for the average person. Too many people, most of them dietitians beeive that if a diet is good for an athlete, it should be great for us. IT AIN"T. In fact, it can be very very wrong. Many body builders become diabetic when they retire because of the massive demands they put on their diet to fuel their body and sport. Maybe a vegan approach is better to those body building- maybe not but in either case, what is good for a competitive athlete id NOT for us

Eva...great question. I have never been a vege but have enjoyed expanding my vege palette through paleo. We have adopted a small measure of compromise by joining the Meatless Monday bunch. I heard about it on Gavan Murphy's blog "The Healthy Irishman". It sounded reasonable and worth a try...

http://gavanmurphy.com/blog/

I truly thing meat is a part of what our bodies need to remain in good health...but with some creative cooking and planning it does not have to be an everyday necessity. Our paleo ancestors certainly had bad days when their luck didn't "bring home the bacon"!

Sure.

Consume most of your calories from coconut, low w-6 nuts and starchy vegetables; supplement with b-12 and krill or algae oil as needed.

I had a raw vegan roommate a while back who I thought was surprisingly healthy. Her staples included soups made from pureed plants (leeks, tomato and squash usually), whole coconuts and ice cream made from cashew & coconut.

She also had a weakness for sushi, so we got her out for fish maybe once or twice a month.

I find it interesting that most of these vegan 'bodybuilders' were bodybuilders who became vegan after they had built their bodies up. Most of them built all their muscle as meat eaters and then found the vegan calling. I bet it's very hard to maintain and impossible to look like them starting out as a vegan. They are probably just using vegan eating to stay lean but probably have made no gains since adopting the diet.

The one puzzler is the guy who founded the site. He claims to have been vegan since the age of 15 and body building since like 17. He claims to have never used steroids. He also isn't huge like many bodybuilders.

I am not sure about the "very" healthy, but for sure a vegan can be much healthier than the general population just from cutting all the processed foods, franken-foods, chemical additives and what not... Unless it's the, very dangerous in my opinion, low-fat vegan (no added fats whatsoever) the person might be quite ok for a long time... I still think that supplementation would be necessary though. And probably a lot of hard cardio.

I think it is essentially impossible to be very healthy without including animal products in your diet, because of the essential fats, proteins, and other nutrients they provide. Nonetheless, there are certainly more and less healthy ways to be vegan. A grain and fruit-based vegan diet, for example, would be worse than one than was based on plant sources of saturated and mono-unsaturated fats, with careful supplementation of known deficiencies.

Yes. But I wasn't a healthy vegan. You have to be careful to avoid nutritional deficiencies. Most people even on SAD still get a lot of certain nutrients that many vegans (especially raw or unsupplemented) don't. I also think that it takes time for the effects to get worse in most people.

But the bottom line is.....if a hunter-gatherer tribe went vegan, their health would suffer greatly, without supplementation, fortified foods, and the modern conveniences that vegans enjoy today...

B12 is the vitamin vegans have to worry about but there is also iron and zinc and stuff like that. Supplementation might take that out of the question (assuming that works as well as getting the vitamins and minerals from food).

Although I admire the consistency of veganism over the self-righteous absurdity of "pescatarian" or other meat-loving "vegetarians". If you want to eat meat , eat meat but don't make yourself out to be something you're not.

Certainly there are some healthy, happy looking vegans. But I think the risk is there with all kinds of vegans, because you have the ethics vegans who don't care about health or nutrition, just animals, and the health vegans that want to believe veganism is the healthiest thing naturally for humans (so they avoid supplements).

Since N=1 is a frequent topic here, allow me this observation, disguised as a question.

Have you ever met Dean Ornish in person? Cadaverous, pale, fidgety. Have met him at social gatherings. Not my picture of health.

I offer the above playfully, not by any means "scientifically." Still, anecdotes can be instructive.

As for a larger sample: Ancestral Health Symposium. My, my. What a healthy, robust, vital, energetic, glowing bunch of non-vegans.

No! How come people lost in the woods or grassy plains starve to death ? You are not a herbivore .

Where's the beef ! LOL

The question isn't whether or not it's possible to be a healthy vegan... it's simply impossible to be a vegan. Those that claim they are are just lying to themselves. Yeah, perhaps it's a noble ideal (one I personally don't agree with but that is neither here nor there), but in practice it is inevitable you are not only using animal products in daily life even though the product may be listed as animal free but you are certainly consuming animals products everyday. Sugar, flour, peanut butter and any nut butter, soy product, soy milk...the list goes on and on. If "vegans" would actually spend the time to research the realities of the lifestyle they are living they would also see they are lying to themselves. Maybe then they would stop the band-wagonning with PETA and spreading ill informed propaganda to those they encounter and perhaps see the error in the thinking.