If you find no labels on particular foods, or if you find labels with little information - which can be the case in smaller stores and in the fruit and vegetable sections of bigger grocery stores - here are a few tips to help you make the greenest food choices:
Eat fruit and vegetables in season. They're more likely to have been grown locally. Fruits and vegetables on the shelf that you know aren't in season are likely to have been imported or brought by road from the other end of the country.
Avoid exotic foods. Some foods and ingredients, such as coffee and tea, likely can't be grown locally; the United States simply doesn't have the climate for them. Find out what grows near where you live by checking out local farmers' markets or by visiting the Web site of your state's department of agriculture, and make the most of it. You'll be supporting your local growers.
Food retailers say that customers want exotic foods from around the world, partly because people are traveling more widely and experiencing foods that they want to continue to enjoy even after they arrive home. Eating green isn't about sacrificing taste or variety or depriving yourself of a taste that you enjoy. If you're making greener choices most of the time, there's more than enough room for an occasional treat from afar.
Look for local businesses. Check out the companies close to you that produce, package, and transport things like bread, rice, milk, and so on. Buying those brands means that you're likely cutting down on the miles your food travels and supporting your local economy.
If you try to buy local produce in order to cut down on the environmental impact of food traveling around the globe, you're likely to end up eating what's in season. And that's how people used to eat: lettuce in the summer and apples in the fall, for example. Quite apart from the environmental and health benefits of eating this way, there's the added pleasure of rediscovering particular foods each year. When the season is over, you can look forward to tasting something again next year instead of becoming used to it all year and taking it for granted.
Buying local produce may not be practical in areas that are especially hot or cold because there are times of the year when pretty much nothing grows. As always, you need to make compromises based on not just the greenest option but the greenest option that's available to you.
It's possible that local producers extend the growing seasons using different kinds of technology: artificial heating and lighting, for example, or growing under poly tunnels. While this setup isn't as perfectly green as in-season, outdoor growing, it can be done in a way that reduces the impact on the environment. Talk to the producers to find out how they manage their growing seasons.