I think both the Sikhs studied by Sir Robert McCarrison:
McCarrison - Nutrition and National Health - Contents
and the Swiss villagers studied by Weston Price:
Nutrition and Physical Degeneration: Chapter 3
would make a better case for the case for a high percentage of meat not being necessary for a good physique.
The Sikhs were a warrior people, tall, well built, and capable of holding the Islamic invaders of India at bay, which would have been no easy task. The rats McCarrison fed on the several different Indian diets make the point just as well.
The Swiss were big, athletic people, sought throughout Europe as mercenaries for centuries and making up the Pope's own bodyguard in Rome. The villagers Price saw had minimal dental caries and, as Price would have put it, "well-formed dental arches". And what goes for teeth tends to go for bones -- and health in in general.
As Stefansson amusingly comments somewhere dairy products are not actually vegetables, although vegetarians are illogical enough to reckon them as such. Both of these cultures used those. The Swiss seem to have been eating meat broths regularly, too, although actual meat-on-the-bone rather infrequently. The Sikhs may have had some animal flesh infrequently -- not sure on that.
It does seem you can do OK on not a lot of meat. Actually, I bet few people posting on this board could boast a mouthful of teeth as good as those Swiss. Few people nowadays don't have "deformed dental arches" and impacted wisdom teeth -- and/or extractions.
Speaking personally, if the meat's around, I'm there. Furthermore, I think that people like Professor Michael Crawford and Dr. Stephen Cunnane have proved their case as regards seafood: it's not really believable that anything else could have driven human encephalization. And that seems to have created a continuing need for the nutrients found therein. So I wouldn't like to take my chances on just meat from land animals. You could probably do OK as regards DHA if you ate the brains of grass-fed livestock, but who nowadays does that? And iodine is an issue, too, as someone already commented.
I think just meat and no seafood (or even fish oil) could be playing ducks and drakes with one's mental health. How much more foolish not even to eat meat?