One of the hot issues in food shopping these days is locally grown food.
According to the strict definition, a "locavore" is one who eats only food grown within a radius of 100 miles. That's the so-called 100-mile diet: make sure that everything you eat is grown within that distance from your home.
Proponents of this plan say that locally grown produce is not only tastier but also more nutritious. You will be supporting your local farmers, your local economy, and your community. By saving the cost of long-distance transport, you will save fossil fuel and reduce the carbon footprint of the food you eat--that is, the amount of greenhouse gases put in the air by producing, harvesting, processing, and transporting the food. How true is all this? The answers are not always clear.
Taste and Nutrition
Locally grown fruits and vegetables picked just before you eat them will almost certainly taste better than those picked before they are ripe and shipped two thousand miles (tomatoes and corn come to mind). Still, not everybody lives close to a farm or even a farmer's market. And if you buy only local foods, variety will be limited most of the year. If produce in the store is fresh and in good condition, it will be rich in nutrients and will taste good, wherever it was grown.
Frozen and even canned fruits and vegetables are nutritious, too. They are convenient--a boon for cooks who have to get a meal on the table after a day's work. It is not true, as some locavores claim, that frozen or canned fruits and vegetables are worthless.
Carbon Footprints and Greenhouse Gases
You may hear you're helping to save the planet by shopping at your local farm stand, but this issue quickly gets complicated. Not all farm stands are right on the farm. Many local farms sell at food co-ops that are not even near the farm. If large amounts of food are transported in big trucks or planes, how does that compare with smaller amounts in many small trucks?
Researchers are now trying to calculate the carbon emissions per food item: what's the energy cost of growing, fertilizing, planting, cultivating, harvesting, refrigerating, and transporting a given item? They come up with many numbers, and it's hard to know what these add up to.
A study done in New Zealand in 2006, for instance, found that meat, dairy, and other foods produced there were grown and processed so much more cleanly and efficiently than British products that they were less polluting, even allowing for air transport to Britain. And a recent British study concluded that transporting foods home in private cars accounted for more environmental damage overall than shipping food by planes. This subject is full of surprises.
Any crop grown anywhere by any method produces some ecological change. This has been true since humans became dependent on agriculture and animal husbandry.
It is thus arguable how much greenhouse gas emissions you save by being a locavore.
Organic or Not Organic?
Local produce may or may not be organic, but it is less likely to be USDA-certified organic. It's expensive and time-consuming to qualify for USDA certification, and small farmers are less likely to apply for it than larger operations, though they may still be using organic practices.
In any event, there is no clear evidence that organically grown produce is more nutritious or safer than its conventionally grown counterparts. Organic methods do have advantages for the grower and the environment. You can ask at the farm stand about how the food was grown.