Today's produce is less nutritious than yesteryear's. But that's not necessarily bad news.

For some food lovers, particularly those who follow the harsh critique of modern agriculture, it's become conventional wisdom that today's fruits and vegetables aren't as nutritious as they used to be. A landmark 2004 University of Texas synopsis of studies that compared what's now on store shelves to vegetables from 1950 found declines of 5% to 40% in certain nutrients among 43 types of produce. Much (but not all) of the produce we eat today does indeed contain lower nutrient levels than that from our parents' and grandparents' days.

But this kernel of truth is missing a bushel of context. One reason for the decrease in nutrient density in today's produce is a relentless, century-long focus on increased yield that has helped feed an exploding population. The industrialization of American agriculture, for all its problems, sustained a huge growth in population and a huge shift in where Americans lived.

"Post-World War II, nearly half the U.S. population was living on a farm feeding America," says Gene Lester, PhD, a plant physiologist with the USDA. "Now we have 1% to 2% of the population feeding the other 99%, and we have much less acreage devoted to farmland." Plus, there are more than 313 million of us today, compared to 150 million in 1950, which means a lot more mouths to feed.

In addition to yield, produce has also been bred for increased disease-resistance and shelf life, ease of transport, and consumer appeal. Occasionally, that has worked in nutrition's favor. Carrots have been bred over the years to be a deeper, darker orange, and their vitamin A levels have more than doubled as a result. But more often, the result has been illustrated by the state of broccoli—selectively bred to hold up better in shipping, but now also with less calcium and magnesium.

Higher yields also have helped control prices so that American consumers spend less of their income on food than almost anyone in the world. In real dollars, it costs about half as much to grow vegetables now as it did in 1950.

Now, critics point out that vast monocultures (huge areas devoted to a single crop), mechanization, and abundant use of chemicals also cause serious environmental damage. That's a valid point, and it prompts a valid question about our food supply: Should food remain so cheap? If environmental degradation is a trade-off for yield, that's a strong argument that we ought to be paying more for dinner.

Those issues will be with us for a long time—and they have no simple fixes. But there is a bright spot: The decline in nutrients may be on the cusp of reversing.

Selecting plants for yield doesn't necessarily have to result in a loss of nutrition; it's just harder to crossbreed for more than one quality at a time. "While focusing on yield, we took our eye off the ball with regard to the concentration of nutrients," Lester says.

Seed developers are beginning to course-correct, and its not just the boutique companies. Monsanto, one of the world's biggest agricultural biotech companies, recently collaborated with Apio, Inc., to release Beneforté broccoli, which has two to three times the level of the phytonutrient glucoraphanin compared to ordinary broccoli. And they developed it the old-fashioned way, with Mendelian cross-breeding. Gardeners, meanwhile, can try one of Burpee's Boost line of seeds with higher levels of nutrients such as carotenoids and vitamin C.

If you're looking for more nutrients from your vegetables right now, Lester advises choosing ones that are largely the same as they were in Eisenhower's time: dark leafy greens.

And buy locally. Because produce loses some nutrients after harvest, you may do better shopping at a local farmers' market, where items are more likely to have been picked recently. These days, buying local produce is getting easier, precisely because the nature of farming in the United States is undergoing more changes. From 2002 to 2007 (the latest year with data), there were more than 75,000 new farms in the U.S., and they look more like what we picture when we think "farm": more diversified crops, less acreage. These are also the farms that have helped fuel the resurgence of heirloom fruits and vegetables—often lower-yield and sometimes higher-nutrition varieties that can date back centuries.

But the single most effective strategy for getting more nutrition from fruits and vegetables is also the simplest: Just eat more of them. In the end, it's not the quality of the produce but the lack of appetite for it that compromises many Americans' diets.