Bear in mind the human body didn’t evolve to have complete nutrition in every meal. Our primate ancestors may have lived on meat for 3 days, then vegetables for a week, then carbs for a week, then killed an animal they lived on for another week.
During a deployment to Afghanistan I once lived on only frozen T-bone steaks for a month, as did 40 other guys. Very small forward outpost. The Taliban ambushed our resupply and we were left with nothing but a container of steaks, all that made it through.
We got tired of it, but health didn’t suffer.
Something in the body allows nutrients to hibernate until the other things it needs to combine with are available. I don’t know what that is, not a nutritionist, but am sure it exists.
The normal human condition is to live with incomplete nutrition meal-to-meal. I am from the USA in the deep south and a common historical daily diet may be just grits for breakfast which is pure carbs, a big chunk of cornbread for lunch which is just carbs, and a supper of again, corn, with some meat like ham or fried chicken added. And that is middle class food, not the food of the poor. I grew up in a middle class southern family and that was my diet. Grits, cornbread , and fried chicken.
I argue that most of humanity lives much the same, the norm being whatever fills your belly whenever you can get it.
But I am convinced the body can do “ok” on very rudimentary nutrition, and when it gets “full” nutrition it is like a nitro boost directly into the bloodstream.