What’s best: fresh, frozen, or canned?

If you pluck a snap pea off its vine in July and pop it into your mouth, that’s as good as it’s ever going to get. But if you eat one that’s been imported from Chile in mid-February, then it’s lost some nutritional value in transit from the farm. (Research from Iowa State University shows that while a local Iowan apple travels only 61 miles to market, a conventional supermarket apple travels 1,726 miles.) If a supermarket’s fresh produce is ever looking a little spent, consider strolling a few aisles over to the freezer section.