I doubt that this is true. In the era of colletion and hunting, the diversity of food is based on the near-by ecosystem, which is larger than modern supermarket.
There is no way that's true. No matter how far a person wandered they're not going to come across a bell pepper, lettuce, carrots, potatoes and any meat they could want.
You're perspective is skewed. Your knowledge only includes the local plants that we have created into our international rummaging choices. Bell Peppers are just one modern variety out from the ~30 species of chilies we've discovered. Same for carrots and potatoes and lettuce. I look at the variety of edible vegetation I can get at the grocery store and the only thing I really think of is it's a good day that I don't have to walk 20 miles to the fruit trees to pick the fruit before all the animals do.
Meat? tons of variety, there are like twenty different cat to dog sized animal species in my Montana wilderness before I even have to get to the large herbivores that have less variety. And meat is special anyways, the mink or weasel you can kill is chock-full of 2-5 years worth of collecting resources from various animal and vegetable sources.
Pine needles "contain more Vitamin C than an orange" (I didn't see it specified if that's by gross weight or dry mass) and make decent tea, and many cultures still boil and eat or cook with pine cones.
Modern crops are amazing, but we are literally surrounded by new and forgotten sustenance. It's not always pretty, tasty, or toothsome, but it's there if you have the time and will to turn it into food.
I'm also reminded of villages that "modernized" by trading their old fashioned cast iron cookware in for aluminum and began to suffer from anemia as a result. Iron is abundant in the crust, and eating mineral-rich clay is still practiced by humans and animals around the planet, but their solution was to put cast iron charms in the new pots for luck. It's possible they were in iron-poor areas, but if they were swayed to abandon their traditions by the appeal of commercial marketing, it seems likely they mught also eschew any dirt-eating practices they once might have had.
Highly sceptical of this if we're talking about the non-animal part of the diet.
Hadza ate only 4 non-animal foods, which is much less than what's available at a supermarket.
Hunter gatherers would've had a more diverse diet when it came to meats, eating the entire animal including most organs, but that's more cultural than what's specifically available at the supermarket (it's pretty easy to get organ meat at the supermarket and especially the butcher, but most people don't opt-in).
Right, but worth noting that raw beef, for example, contains a lot more nutrients than cooked beef[1], and includes most of the essential vitamins you would need to live.
Other parts of the animal, like the liver, would provide sources for A and B12, etc.
> Because of its content in highly valuable
> nutrients such as iron, zinc, selenium, fatty
> acids, and vitamins, meat is a unique and
> necessary food for the human diet in order
> to secure a long and healthy life, without
> nutritional deficiencies.[2]
That's a bit of a myth. Life expectancy was vastly less than it is now, but that is because of infant mortality, death in childbirth, lack of emergency medicine, etc. Those that survived all that lived about the same as today, about 70-80 years: