Kiwi, I’ve studied this science a lot, and from everything I read, it seems that high levels of meat, eggs, and saturated fat and cholesterol, people that are already overweight will respond negatively, whereas people that are on good shape may respond with no issues.
It has something to do with how the body (liver?) regulates the release of cholesterol.
This is why we see the stories of people doing well on keto type diets, while the science mostly leans towards high protein (excessive) high fat diets killing people.
The other issue is that high meat/high saturated fat diets kill people slowly. So people WILL lose weight on this type of diet, all while slowly dying from cardiovascular disease.