My current theory:
Vitamin A is poisonous to the body.
Fat consumed with plant vitamin A beta carotene increases the absorption of this plant toxin. Animal vitamin A is highly absorbed in the body.
Milk is fortified with vitamin A and the things in milk make it highly absorbed.
Muscle Meat has fat, and small amounts of vitamin A
If you eat vegan, eating veggies with a lot of vitamin A in combination with oils, fats, you will absorb a lot of it.
Beta-carotene conversion to retinol is not a regulated conversion, as some have concluded. Vitamin A toxicity is possible with beta-carotene.
It explains how saturated fat has been demonized by the health community, since people who eat more fat have worse health outcomes.
It explains how animal protein consumption is associated with poor health outcomes.
It explains how a lot fat diet could be beneficial. Less vitamin A absorption.
Many people switch to vegan and some do really well, however some don’t, maybe its too many sweet potatoes with olive oil. Vitamin A increases the need for protein in the body. When you lose fat your fat stored vitamin A poisons your body more, so for some weight loss could be a poisoning. Some will go back to meat and get a euphoric feeling, perhaps its just needed to detox that excess vitamin A, a healthy non toxic person needs less protein. Maybe they don’t eat enough beans to clean out their toxic bile.
The poisonous combination: Vitamin A rich foods in combination with animal fats, seed oils, olive oil, coconut oil.
Many high vitamin A foods are relatively new in the human diet, like tomatoes, sweet potatoes, orange carrots, cod liver oil, vitamin A fortified milk.
It must have been known that vitamin A was toxic before, but we have forgotten.