What kaplods said.
There's a huge body of research on nutrition, and attempting to distill it down until a few basic foods is an impossible feat. There are as many ways to have a "healthy" diet as there are posters on this forum, foods vary naturally in nutritional value, prices vary seasonally and from locality to locality.
What resources you have available to you vary as well. I have a friend who can harvest salad from nearly anyone's front lawn, and it's a highly nutritious and free option, but requires that you know local plants and are comfortable foraging. Locally I could get fresh seafood or fish for minimal cost in time/equipment/licensing, but again, you have to have knowledge of the area and the interest in doing so.
Adding wings to caterpillars does not create butterflies, it creates awkward and dysfunctional caterpillars. Butterflies are created through transformation. - Stephanie Marshall