He talks about how for simplicity's sake (yield, shipping, shelf-life, etc) half of America's commercially grown broccoli, for example, is one high-yield variety. The great majority of chickens raised in this country are the same hybrid. More than 99% of turkeys raised here are the same
Why does this matter? Says Pollan:
With the rise of industrial agriculture, vast monocultures of a tiny group of plants, most of them cereal grains, have replaced the diversified farms that used to feed us.Think about what a typical farm grew and raised 100 years ago. A huge amount of different fruits, vegetables and livestock. Now, things have changed, says Pollan:
This simplification of the agricultural landscape leads directly to the simplification of the diet, which is now to a remarkable extent dominated by--big surprise--corn and soybeans. You may not think you eat a lot of corn and soybeans, but you do: 75 percent of the vegetable oils in your diet come from soy (representing 20 percent of your daily calories) and more than half of the sweeteners you consume come from corn (representing around 10 percent of daily calories).Yikes.
Much of the corn and soy crop goes into feed for the animals we eat--simplifying their diets, which is unhealthy for them. But our health is being dictated by the amount of corn and soy in our foods. Again, Pollan writes:
...Today corn contributes 554 calories a day to America's per capita food supply and soy another 257. Add wheat (768 calories) and rice (91) and you can see there isn't a whole lot of room left in the American stomach for any other foods....Today these four crops account for two thirds of the calories we eat. When you consider that humankind has historically consumed some eighty thousand edible species....this represents a radical simplification of the human diet.
The problem is that humans are omnivores. We are built to get our nutrition from a wide variety of foods, not just these four.
Another problem with industrial farming is a loss in nutrition in the crops themselves. The USDA has shown that 43 crops they have traced since the middle of the 20th Century have decreased nutrition.
Industrial fertilizers are part of the problem. Crops grow quicker and don't have the time to build up the nutrients they would if they were grown naturally. They also give the plants an easier time to get the nutrients they need, so their roots aren't as deep and can't reach down into the soil where the essential minerals dwell....You have to eat three apples to get the same amount of iron as you would have gotten from a single 1940 apple, and you'd have to eat several more slices of bread to get your recommended daily allowance of zinc than you would have a century ago.
This is a big issue and way too much for me to write about here (read the book). But you get an idea of how things like this are all intertwined with our food and our health. More later.