Originally Posted by
noglider
I think there would be a great deal of vitamins and minerals if you didn't have a variety of plant food. And you need fiber, too. Also there have been studies on how a high fat, high protein diet can cause inflammation, premature disease, etc. I've read about serious problems with a great many kinds of diets. There certainly is an element of guesswork, so you have to guess what's right for you after learning what you can.
A diet consisting solely of eggs, fish, and meat (with the organs) would actually cover all essential nutrients!
However, this is (almost) a minimal set of food groups for getting all essential nutrients, one can always add more things, and personally I think that one should. Unless you are suffering from some food allergy or related condition and need to drop to a baseline in order to reconstruct your diet, there is no reason for restricting your diet that much (or unless you want to of course).
That said I've never met a long-term carnivore in person, I have a colleague who used to be a boxer in his national team when he was young and he only did steak and protein powder for 6 months, he had no issues and felt great, but it became boring. I have also spent a good week or so clearing the fridge of goat cheese, eggs, and butter when I had an accident and couldn't move around easily to do the groceries, and I healed up super fast.