food is complicated
Presumably it is possible to find the right combination of nutrients in nature, without taking supplements. Sure, our understanding of "right" has changed over time, but for at least several decades I gather that we've grokked the importance of basic vitamins and minerals, and I don't remember supplements being nearly so prevalent a few decades ago as they are now. So how does one get enough good stuff (calcium, protein, vitamins) without getting too much bad stuff (cholesterol, sugar, excess calories), without supplements? What is the canonical modern (wo)man supposed to eat? (The last time I looked at the food pyramid it wasn't very helpful for gleaning details. It also assumed 2000+ calories/day, which a sendentary blob like me shouldn't eat.)

no subject
Another really good book I read recently is "What to Eat" by Marion Nestle, a nutritionist. She organizes the book around sections in your average grocery store, and goes through each section explaining not only the nutritive properties of the foods, but how to choose between the various options (for example, organic v. not, hormone free v. not, genetically modified organisms, locally grown v. flown in from CA or international etc.) and the various aspects of marketing and what they are based on (shelf space, placement of common items, pushing impulse purchases, burying useful items deep in aisles so you walk past more products, etc.) The book has a lot of good take-aways, and it is easily digestible both as a straight read, and bouncing between interesting sounding chapters.
One concept I got from the Nestle book was that the food pyramid is to a large extent a political construction. Not that it doesn't have some good advice, but special interest lobbyists from the food industry influence what is suggested. So they can't, for example, say things like "no really, cut down on sugar" because the sugar lobby will be very upset. I'm guessing detailed advice mostly falls into this category.