Just look to biology for the answers, its there if you pay attention.
The leader of a wolf pack gets first pickins at a kill, and it always eats the liver first.
Large carnivores elsewhere eat organs first as well.
There's a growing body of research for something that's being called the "carnivore" diet, and there's a sub-movement called "eating nose-to-tail" that seems to be, as best as I can tell, led by a physician named Dr. Paul Saladino, M.D., although the usual suspects are always on his podcast, or he's on theirs and/or associated with him: Dr. Dominic D'Agostino, Dr. Shawn Baker, M.D., etc.
Its basically exactly what you would expect... eating a lot of heart, liver, kidneys, along with skeletal muscle, etc.. I tried to do it, but I love things like french fries, roasted potatoes, roasted Brussel sprouts, etc. way too much. The biomarkers on this diet look amazing, but its always the same "problem". The people who are evangelical about eating this way are also huge into fitness, oftentimes spending an hour or more a day exercising.
I'd like to see 100 total lazy fatasses on a nose-to-tail carnivore diet and 100 total lazy fatasses on a vegetarian diet for 1 month, 3 months, 6 months, 1 year, and 2 years, and do weekly workups on them... blood pressure, fasting glucose, post-prandial glucose, and so on.