Salads carry a huge profit margin at restaurants.
Everyone loves to eat healthy or at least believe that they're doing so. A salad is a great healthy choice (until you slather it with dressing, which is nutritionally awful stuff.)
But a house salad is composed of the cheapest ingredients ever: you've got tomatoes, iceberg lettuce, shredded carrots, cucumbers, a little shredded cheese and croutons. But you can charge at least $7.99 for something that simple. And you can offer a protein to go on top for extra profit.
And truthfully there's very little nutrition of any kind in that ingredients list. When you've grown your lettuce in impoverished soil, and your tomatoes are picked green and "ripen on the vine" or artificially induced, there's not much they can offer. Someone once said to me, "How do you kill an iguana? Feed it nothing but iceberg lettuce."
Now don't get me wrong, salads are a great part of anyone's diet and we should never neglect salads, because they're certainly preferable to a burger and fries every day. But vegetables, being cheap to produce and profitably marked up, are hindering many a plan to stay healthy.
Developed countries do not build food plans based on the good nutrition of the populace, they're based on maximizing shareholder value for the agribusiness conglomerates, and subsidizing the most strategically important crops. We could eat corn until we are literally blue in the face.
As long as your corner convenience store is jammed with corn chips, beef jerky, and beer, Americans will never eat healthy, even if the Food Pyramid is rehabilitated. I have seen some good progress made on bringing fresh produce to food desert areas. I hope those initiatives succeed and continue.