Is the premise that humans do equally well on a mostly plant diet or a mostly meat diet? The implication of that premise is that we are both herbivores and carnivores. I know of no species that is both. It's either or. We might be omnivores, but that's just because we intentionally eat all kinds of things, some of which don't actually nourish us, which is what food is supposed to do otherwise. Rather, if it doesn't nourish us, it must not be food for us. Is rice food for humans? Ah, didn't think to ask the question, didja. The rice "diet" is used explicitly as therapeutic. However, we call it a "diet" because we believe rice is food for humans. We don't even question that assumption. If the thing consumed was aspirin, we wouldn't call it a diet, we'd call it a treatment, cuz we're not that dumb to think aspirin is food for humans.
Remember, many, many, many medical treatments are derived from plants, and we're totally not confused about that. We call them drugs. It's quite possible that the rice "diet" is therapeutic, not because rice is food, but because of some other factor, i.e. it displaces the thing that otherwise makes us sick (low-carb does that too, only better), it contains some substance that acts on the disease (low-carb does that too, only better), etc. The Nothing "diet" is equally therapeutic, and we're totally not confused about that either. But we call it fasting, or starvation. It certainly does not nourish us.
It's quite possible to produce the appearance of therapy in the context of obesity for example, but in fact produce the opposite extreme in the form of emaciation. Well, if that's possible with obesity, maybe it's just as possible with diabetes type 2. There's the appearance of therapy, but in fact we have the opposite extreme, that yes give all kinds of indication of improvement, but in fact should be seen as worsening of the existing condition, just on the opposite end of the same spectrum. Just saying.
Alternatively, we could just eat actual genuine food that does what food does, and still see the same, nay better and best improvements possible. For two reasons. 1. It's therapeutic because the thing that makes us sick is removed, just like when we remove arsenic from, eh, an arsenic "diet". 2. It feeds us cuz that's what food does, and in doing so directly acts against the disease.
Let's imagine we go through with any kind of method to treat the disease, what then? If it's merely therapeutic, once the disease is treated, we can cease the therapy, yes? So what then, go back to our arsenic "diet"? That's absurd. Keep up the therapy? Why, the disease is gone, the therapy is now unnecessary, and likely to become detrimental, especially if it takes the form of non-food, which rice probably is, and displaces actual genuine food, which would normally nourish us, we end up malnourished. How about get unconfused, use whatever therapy you want, then stop the therapy, don't go back to our arsenic "diet", eat genuine food for a change. Or just eat genuine food right off the bat, then use whatever therapy we need for whatever else this genuine food can't fix, which is likely to be the case anyway.
So what's food anyways? Can't find out with disease/therapeutic experiments, must use healthy subjects, just like in that famous semi-starvation experiment. It's obvious they stuff they ate ain't food. Just like in that famous all-meat experiment too. It's obvious it's genuine food they ate. Well, between the two, which one can be expected to be most beneficial and the least detrimental in disease/therapeutic experiments?
Right, so let's start with the correct premise, Denise.