I tend to agree that, in many cases, more "natural" is more "healthy" but my main caveats would be:

1. "natural" does not automatically mean better. Depends on the context and many other factors.

2. Determining what is "natural" is also contextual based on what timeline you are talking about and what geographic location. To say "paleolithic ways of eating are healthier" is meaningless unless you think that we a. know exactly what they ate back then and b. every human had access to the same foods regardless of where they lives on the planet