[wyager]

It's not just sugar - any carbohydrate which a bacterium can easily metabolize to sugar (i.e. most of them) is a hazard. Grains, tubers, etc. are all dangerous from a dental perspective and have only been consumed in calorically significant quantities after the advent of agriculture.

[AlotOfReading]

You're correct that any carbs can help form plaque, but humans have been getting significant numbers of calories from them since before we were H. sapiens.

[wyager]

This is only plausible for humans in tropical areas. It does not stand to reason for humans north of (conservatively), say, 40º. Even in humans in areas with calorically significant quantities of carbohydrates available, fossil records suggest they probably preferentially ate ruminants, same as anyone else.

[AlotOfReading]

Most of human evolution occurred below 40N, so even if that point were correct, it would at best be limited to the adaptive behaviors of a very small group of human ancestors.

However, there's plenty of evidence suggesting that there wasn't any such regionally adaptive behavior. The original find that suggested starchy plant consumption in H. erectus was analysis of the Dmanisi fossils at ~41N. Later work tying these sorts of results to typical European Neanderthal diets has been done for North Sea sites (~50N). Of course, Neanderthals never went much farther north than that due to the climate. As for AMHs, I've seen papers of sites near Smolensk (~55N) indicating moderate to heavy starchy plant use. That's not far from the glaciation line.

Moreover, there are fairly convincing arguments that a nearly pure-meat diet doesn't work in winter due to the general lack of fat (e.g. https://doi.org/10.1016/j.quascirev.2009.11.016 ). There are caveats and workarounds here, but this whole idea that high-latitude hominins had limited, homogeneous diets is on increasingly shaky ground.

[asdff]

They are only dangerous if you don't brush or floss. With respect to ancient cultures a little twig is a damn effective dental cleaner and about as good as a modern toothbrush.

[wyager]

People today who brush regularly still have way more rotted-out teeth than people who didn't eat significant quantities of carbohydrates. They are dangerous even if you brush.

[jkepler]

Growing up, my dad often said that raw carrots are "nature's toothbrush" and he would encourage us to end any picnic lunch with carrot sticks, not with a sugary dessert. Can carrot sticks function like a little twig in terms of knocking undesirable food gunk off teeth?

[hypertele-Xii]

Can't confirm but this feels right. Chewing on carrot breaks loose any food that sticks to my teeth.