Low meat diets are fake science.
Before cultivation (farming) we ate meat, fish, fowl, woodland berries and nuts and some tuber plants. We were hunter gatherers. The human body was adapted for this diet. With the advent of farming population exploded swiftly due to abundance of food that was mostly carbohydrates. Our bodies were not designed for this diet.
Oddly the carbs gave us large populations and civilizations of great grandeur though they were not the best of food.