What I’ve Learned - Vegan diets don’t work. Here’s why
There have been observations that eating processed modern foods is in correlation with weakened body and worsened health as opposed to traditional nutrient dense meat heavy diets. One of the examples is the prevalence of crooked teeth and tighter cavities after the rise of modern foods.
It has been shown that in addition to all the protein and other macronutrients, meats contain a lot of other vitamins and compounds that our bodies have evolved with and need to grow in the ideal, most healthy way. As with teeth, all of our bone structure is dependent on these nutrients and vitamins, which affects the size of the skull, shape of the face and body, strength etc.
There is also a strong correlation in height and animal protein (in paticular, dairy) heavy diets.
Some examples of vitamins that mainly come from animals: Vitamin A comes from beta carotene, from vegetables, which needs to be converted to vitamin A (the conversion is about 12-21:1, the more you eat the worse this rate becomes). It also comes from meat directly without conversion. Vitamin D is only found in animal foods (and some specific UV exposed mushrooms, algae). Most people do not get enough from the sun if they live above latitude of 37 degrees (maybe only during summer). Vitamin K2 comes from fermented foods and animals foods. It comes from livers, egg yolks, hard cheese, full fat dairy. Vitamin B12 is a famously difficult vitamin to get from supplements, which may not work exactly the same as the one from animals, also it takes long to exhaust the bodys own stores of B12, so many may not even notice the defficiency until very late.
Interestingly when fed raw meat to kittens and cats, they showed far more healthy bone structures, vitamin levels and overall health than those who ate cooked meat. Even more interesting is that for the cooked meat cats had worse and worse conditions over multiple generations compared to raw meat eating generations of cats. There were also mixed groups, which showed that if the diet was more or less 50% raw then there were no significant development issues. Note that the default healthy diet for cats differs from that of humans, so going full raw may not be the best solution, although at the time of writing meat only diets have shown no deficiencies or problems compared to regular or vegan diets (the effects take far longer to appear in human from generation to generation). But it is evident that for the last generations humans have been getting weaker, getting crooked teeth, worse bones, having worse eyesight (Why so many people need glasses now), less fertile, more depressed etc.
It is extremely hard. at the time of writing, to imidate natural foods using current science which is just incomplete. Examples include the baby formula which is still not a perfect replacement for breastfeeding. Or the Impossible Burger, which may taste like they have successfully replaced meat, but contains dubious and suspicious ingredients for meat, some of which have not been tested for safety.