We’re good survivors for sure, but try eating only deep fried donuts for a year and let me know how omnivorous you feel.
If it was the case, we wouldn't have an article like this. We would have very obvious results, and we don't. Some claim we do, but if you look closer, it is not obvious at all.
Note that by "it doesn't matter", I don't mean that anything goes. Only eating deep fried donuts is not good, for the same reason eating only apples is not good, you won't get everything you need from a single food source. If you do that, you will get what are now very obvious and easily identified diseases, like scurvy, anemia, etc... Also, eating too little or too many calories is also not good, especially too little, but the effect (starving to death) is even more obvious.
What I meant by "it doesn't matter" is that with a varied diet and the right number of calories, the details don't matter. And I am convinced that a base diet of fried donuts to the appropriate amount of calories, with supplementation (vitamins, ...) to compensate for deficiencies is fine, or at least, not terrible.
And I also believe that "the appropriate number of calories" is the tricky part. Hunger mechanisms are supposed to regulate this, but they are not adapted to modern society, where rich food is plentiful. Hence the psychological aspect, which Ozempic targets.