I heard an interview of Michael Pollan yesterday on Talk of the Nation. He made some important points about nutrition that bear repeating. He's fond of saying "don't eat anything your grandmother wouldn't recognize as food". That doesn't mean your grandmother specifically, but anyone's grandmother, whether she was Japanese, American or African. The point is that commercial food processing has taken us away from the foods, and traditional food preparation methods, on which our bodies evolved to thrive. At this point, we don't know enough about health to design a healthy synthetic diet. Diet and health are too complex for reductionism at our current level of understanding. For that reason, any departure from natural foods and traditional food processing techniques is suspect.
Mainstream nutrition science has repeatedly contradicted itself and led us down the wrong path. This means that traditional cultures still have something to teach us about health. Hunter-gatherers and certain other non-industrial cultures are still the healthiest people on Earth, from the perspective of non-communicable disease. Pollan used the example of butter. First we thought it was healthy, then we were told it contains too much saturated fat and should be replaced with hydrogenated vegetable margarine. Now we learn that trans fats are unhealthy, so we're making new margarines that are low in trans fats, but are still industrially processed pseudo-foods. How long will it take to show these new fats are harmful? What will be the next industrial fat to replace them? This game can be played forever as the latest unproven processed food replaces the previous one, and it will never result in something as healthy as real butter.
The last point of Pollan's I'll mention is that the world contains (or contained) a diversity of different cultures, living in dramatically different ways, many of which do not suffer from degenerative disease. These range from carnivores like the Inuit, to plant-heavy agriculturalists like the Kitavans, to pastoralists like the Masai. The human body is adapted to a wide variety of foodways, but the one it doesn't seem to like is the modern Western diet.
Pollan's new book is In Defense of Food. I haven't read it, but I think it would be a good introduction to the health, ethical and environmental issues that surround food choices. He's a clear and accessible writer.
Merry Christmas, happy Hanukkah, and happy holidays to everyone!