In case it's of interest —
Nagel notes that Australian Aborigines ate, according to Weston Price, 4.6 times as much calcium as Americans of the day, 6.2 times as much phosphorus, and ten times as much the amount of fat-soluble vitamins.
If you haven't got raw milk from grass-fed animals (and dairy products made from that), he says you'll need to get these nutrients from seafood, including the organs, heads, brains, eyes, and eggs of fish and shellfish, and from the the organs of land animals. The native Australians would have done that.
Nagel seems very down on cereal grains. He says what Price couldn't have known about in the 1930s were antinutrients like phytates. These seem to have a major role in tooth decay. It's not that you can't eat these and still have cavity-free teeth (as the Swiss, Hebridean Islanders, and the Dinka demonstrate); it's that, if you do, by golly do they take some careful preparation. (c.f. the note above on the Swiss rye bread.)
He also claims you need to avoid raw nuts because of antinutrients, and he says cocoa is high in phytic acid (as well as usually accompanied by a lot of sugar), which I hadn't known.
There's more on calcium and phosphorus. He says it's been shown by a dentist called Melvin Page that it's the calcium–phosphorus balance in the blood that's important. You need sufficient supplies of both minerals in the diet (and of fat-soluble vitamins for them to be utilized). However, there's more to it that that—for example, blood sugar fluctuations can cause the balance to fluctuate, which he says can be bad news:
A ratio fo 8.75 mg of calcium per 100 ml of blood, and 3.75 mg ... with normal blood sugar levels creates immunity to tooth decay. ...
When there are blood sugar spikes, minerals like calcium are pulled from our bones. When the amounts of calcium or phosphorus deviate from these levels ... minerals are withdrawn from the teeth ... resulting in tooth decay or gum disease or both