The ultimate secret of all fad diets

I'm going to save you a lot of time trying out different crazy diets and give you the drop of truth behind the mountain of bull shit.  OK, here goes:

Don't eat lots of any one thing.
Eat lots of different things.
Avoid processed foods.
Eat lots of plants.
If you need to add extra flavor to make it not taste repulsive then don't eat it.

OK?  That's it.  You want a good diet, there it is.  If you really want to get finicky some things that may have a hard to measure additional benefit:

Avoid weird chemicals (that's partially covered in not eating processed foods, but also means you avoid things with chemicals sprayed on or injected into them.)
Eat stuff as fresh as you can get it.

And to sum it all up in one simple concept: eat like a crazy forest hermit.

Elaboration:  eat like nature intended us to eat.  That's quite variable if you look at different 'primitive' peoples.  Extremely variable, depending on the environment.  But if you can understand and apply this principle in a non-insane way, you don't need any of the others.

There.  Now for god's sake stop giving people money to tell you fractions of this over the course of weeks and months and years and spend that time and money eating good food.