The frugivore thing does make sense. Consider what primates eat: fruit, mainly. Oh, and bugs.

As for "bad science" well, it is annoying that so-called scientists and experts cannot even agree on what is a healthy diet...but some things we know.

We know preservatives and processed sources of saturated fats are bad for humans. We know processed sugars are VERY bad for humans, exacerbating some of our worst health problems including tooth decay, alcoholism and diabetes. We know the body DOES digest food more efficiently when fewer foods ar eaten at once, particularly if one avoids combining proteina nd starch together at one meal, and the best aporoach to this is the "mono-diet" or one food at a time...The typical "English" Sunday dinner or Thanksgiving spread wreaks havoc because of the bad combining...

We know that most people are far less active today than they were in the first half of the last century. We know we die in greater numbers from diseases directly related to diet than at any other time in our history. We know that eating too much of anything is not a good thing. We know that eating a food as close as possible to its "live" or natural state is far more healthy than eating food which has been freeze-dried, frozen, canned, smoked, pickled, dried or otherwise preserved.

I highly recommend a book called "Native Nutrition." It details the history of the diets of a number of indigenous populations throughout the world.