Simple food is best–best for the flavor and best for they nutritional benefits. It seems the more we try to tinker and improve, beyond a point, the more we mess it up. Not that there isn’t a place for gourmet cooking now and then, but really your options on what to do with the food usually amount to overcooking it or over-refining it., or adding extra fat and sugar and salt. That is why most restaurant food is simply not healthy. Historically, the poorer classes are healthier because the could never afford the refined and rich foods that the rich could (my how that has changed). Diabetes was a rich persons disease almost entirely up to the twentieth century.
I love simple summer vegetable meals. Some potatoes, fresh beans, some white sauce, corn on the cob and a fresh garden salad and you are eating good and packing in the nutrition. This is a proper peasants meal, but it is delicious in its simplicity. Simplicity can be a bad thing, I guess, if your idea of simplicity is to open up a can or two. Getting fresh food seems to be a key in good nutrition, that has probably been overlooked for the most part.