How Is Is Ought

I don't think the "naturalistic fallacy" is a fallacy. The natural state of the world does cohere with the moral state of goodness and health. "Is" does usually mean "ought." If you try to move away from real human nature in the cultures you create it becomes bad because it makes both you and the culture disharmonious with what you actually are and what your genetic traits relate to. If you create a culture designed for parrots it wont work well for humans and it is therefore bad for humans. The task of course is in defining human nature. Science and religion don't always define human nature the same way, which has caused conflicts between them for centuries.

Fortunately there is much knowledge regarding real human nature mainly from the sociobiological sciences descended at least from Darwin to E.O.Wilson, which can also be seen in many human cultural traditions. Here we find that across human history to this day human nature has been kin-centered, gender defined, age-graded, heterosexual marriage-making, hierarchical, ethnocentric, even xenophobic, and religious-making, among other things, with group-selection as the primary unit of successful selection, followed by individual selection. Cultures can operate for a time with behavior that goes against real human nature, with such experiments as Marxism, but the culture is always eventually pulled back by the biological and genetic leash of real human nature to cultures that better reflect real human nature, within the environments humans find themselves living within.

So we ought to create cultures that reflect what human nature really is, and that it is good, and when we do not that is bad. This can be seen and proved as true..If we want to gradually try to change human nature through evolution and culture that is another subject.