"Food, Inc."

American agriculture changed more in the past 50 years than it did in the previous 10,000 years since humans started cultivating grains and domesticating cattle, pigs, and poultry. This affects all Americans, but none more than those of us who have diabetes, which started its steep rise at about the same time that our farms became so much more efficient under the management of just a few huge multinational corporations.

This correlation certainly isn't proof that modern agriculture caused the rise of diabetes. It remains, however, a likely suspect.

Neither can we fairly claim that the giant corporations that control most of American agriculture are the cause of anything more than being efficient. These companies are doing what companies are supposed to do -- making a lot of money by doing what all companies try to do.

The root of the problem is our government. The federal government of the United States of America set the conditions under which the great consolidation of American agriculture took place. This is our "farm policy."

This is what I come away with after watching the new documentary film "Food, Inc." twice and reflecting on it at length. "Food, Inc." played to limited engagements in our theaters earlier this year and just a few days ago became available on DVD. Since I missed it in the local theater, I made sure to see it as soon as it came up on my Netflix queue.

This documentary stars two guys who play themselves, both of them among my heroes. Investigative reporter Eric Schlosser wrote Fast Food Nation, and Michael Pollan who wrote The Omnivore's Dilemma and In Defense of Food.

Pollan, a professor of journalism at the University of California, Berkeley, has long been a critic of the American farm policy that supports five commodity crops with about $25 billion every year. This is why corn, soybeans, wheat, rice, and cotton seem so inexpensive.

They only seem inexpensive. Food produced from these commodities is actually expensive, as traditional farmer Joel Salatin of Polyface farm says in the film. Economists call this external costs or negative externalities.

We pay for all of these commodities that we eat in other ways too. Three of these commodies are very high glycemic, meaning that they spike our blood glucose levels. All the corn that we consume directly, in thousands of products on supermarket shelves, and in animal feed contribute to our high blood glucose levels. Wheat and rice are two other grains that spike our blood glucose levels more than practically anything else.

But the huge corporations that have taken over American agriculture get most of the blame in the film and from other reviewers. They are an easy target.

Today the top four beef packers control 80 percent of the market. The film names them as Tyson, Swift, Cargill, and National Beef. "Tyson is the biggest meat packing company in the history of the world," Schlosser says.

Three other huge companies, ConAgra, ADM, and Smithfield, also get their share of criticism in this film. In Tar Hill, North Carolina, Smithfield operates the largest slaughterhouse in the world. Like all of the companies that this film singles out, they certainly do their share of lobbying Congress. And again, that's just what our system is set up to do.