Eating Locally appears less important in terms of GHG.

Well damn that's kind of disappointing.  There are still lots of benefits from buying local, particularly at a farmer's market where you can ask the farmers how they grew the food and whether it's organic, etc.

I agree good list in the Seventh Generation article.

Thanks for the post.  It is a little disappointing, but makes sense.

As Dana points out, there are other reasons to eat locally.  I get all of my meat directly from a farm 5 miles down the road.  Part of the reason is that it supports a local economy.  The farmer shares my interests and I am helping create demand for a good product.  These all factor into my decisions.

The list from 7th Generation does provide some good guidelines.  I would like to see more detailed studies of other parts of the food system, particularly added ingredients.  It's relatively easy to compare orange juice in terms of environmental impact.  When you start adding things to it is where it gets tricky.  You can get orange juice with added vitamins, for instance.  It should be considered that those extra vitamins are usually made at another facility and shipped to the juice manufacturer.  Chemicals (vitamins) have a shelf life.  Inevitably there will be waste.  Some of these chemicals are very hazardous in high concentrations.  Some are flammable.  The equipment used to make these chemicals all need to be cleaned throughly quite frequently.  This involves a lot of powerful chemical cleaners (more processing and transporting of these) and tremendous amounts of hot water.  Some of these chemicals are bought and stored in bulk.  In my company that involves a lot of moving pallets with gas-powered forklifts and movement between production and warehousing (sometimes off-site) facilities.  And on and on it goes.

This does not even begin to consider those mysterious "natural flavors" found in nearly all foods, even organics.  These flavors are comprised of a lot of different chemicals.  Using what I have already shared, you can imagine the difficulty in measuring the environmental impact of dozens, sometimes hundreds, of chemicals all being produced and shipped to a facility to make the flavors, which then ship that (usually hazardous) product to the food manufacturer.  It's quite a process!

Basically, the less ingredients the better.  Another importnat factor in food buying, but one that is difficult to measure in terms of overall impact.  I find it best to err on the side of caution!

To follow Michael Pollon's advice, eat food, mostly plants, and not too much!

Huh, this comes from the Seventh Gen article:

Though the average meal in the U.S. travels some 1,500 miles before it is served, researchers at Carnegie Mellon University have found that a full 83% of its GHG emissions come simply from growing and raising that food on the farm. Transportation accounts for only 11%, and transportation between the grower and the seller, which is the portion of the equation that's largely zeroed out by eating locally-produced foods, is responsible for a scant 4%.

In some ways, I'm sure we have to take the Tropicana study with a grain of salt because their product is national...and clearly not produced locally for the vast majority of consumers.  Even so, it's interesting.