Thousands of years ago, people foraged and hunted for food. When populations increased, people learned how to farm and propagate plants and animals so that more people could be fed with regularity. Farmers used to grow many foods, rotate crops, and use natural fertilizers. Foods grown nearby were eaten fresh and primarily in season.

Today, we depend on the global economy to produce and supply our food. Are the foods that are shipped from far away just as nutritious as those grown locally? A ripe, juicy tomato from your backyard has about the same measurable nutritional value as those whitish-orange hothouse tomatoes on sale in winter.

But, even though they have the same “scientific” measurements, our intuitive measurement tells us they are different. The life in food gives us life. Once a plant is picked or an animal killed, a grain split or milk homogenized, it begins to lose its enzymatic activity. Transporting foods over long distances diminishes their life-giving capacity.

Statistically, canned, frozen, and packaged foods often contain great nutrients, but we know instinctively that they’re different from fresh or homemade foods. They don’t have the essential enzymes that are critical aids to digestion and metabolism. Fresh fruits, vegetables, local fish and game, grains, beans, nuts, and seeds give us these necessary enzymes.

If your body doesn’t have to work overtime making enzymes, it has more energy for other processes. Whole foods are in balance with themselves and with nature. When we eat them, we benefit from their balance. Not only are our foods processed, but they are also preserved.

Preservation and packaging of food has killed much of the bacteria that cause food to spoil, helping to lengthen shelf life. But at the same time, we have also destroyed the beneficial bacteria and enzymes that help maintain our health. Our soils are being depleted. Most food in America is grown on corporate agrifarms that grow monocrops.

Chemical fertilizers add only the nutrients necessary for healthy plants, not nutrientrich foods. Between 1993 and 1997, 19 to 24 percent of foods tested positive for pesticide residues. Pesticides have neurotoxic effects and can cause damage to our nervous systems.

They are especially harmful to children whose small bodies are exposed to more pesticides per unit of weight than adults. The good news is that organic farming and integrated pest management are gaining momentum. Most of our produce is hybridized. Its nutrient value is often sacrificed for pesticide resistance, ease of transportation, or appearance.

Many of these hybridized foods look or taste better than their old counterparts, but corn, for instance, has 14 percent less protein now than it did forty years ago. Throughout the world groups of people now collect seeds from nonhybrid food plants and grow them. Someday we may be very grateful for these pioneers who are helping to protect biodiversity.