There is a very real difference between:
2000 calories of a beef roast with a bunch of broccoli in the fat and grease and butter, full of rewarding yummtasticness, vs
2000 calories of potatoes fried in corn oil (chips), or
2000 calories of corn syrup and white flour and powdered cocoa and soybean oil (brownies), or
2000 calories of low fat sunchips, or
2000 calories of ricecakes, or
2000 calories of organic pineapple and mango juice.
BIG BIG difference.
If you eat the beef roast, you are meeting every single nutritional need for the most part. Minerals, vitamins, protein, fatty acids, caloric energy (glucose/fat). This is the only item on the above list where a person can eat it, eat NOTHING else, and have a totally functional thriving healthy biological machine; in fact, odds are, if you ate an entire beef roast + broccoli to catch drippings, your health would increase relative to the inferior quality foods you would otherwise eat (e.g. peasant food such as starches like potatoes and rice and fruits which are far less nutritious, or god forbid, junk food crap like ramen and bread and chips and cakes).