What you eat is of course closely linked to your health because your body transforms what you eat into energy, and the better the quality of the food (less pesticides and nutrient rich soil), the better your energy and your body's ability to repair its cells and self-heal.
But eating, as Wendell Berry, the great environmental activist and poet, said, is also an agricultural act. As such it is just as closely linked to the health of our environment through the way we practice agriculture, as it is to your own health. So what you eat has vast implications.
You may think that on an individual level eating a conventional versus a sprayed pear may not make much of a difference. But think about the implications of what 325 million people, the current US population, eat. It makes a difference if you grow your own pears, buy conventional (sprayed with pesticides and artificially fertilized) or organic pears (more natural ways to prevent pests and enrich the soil). Last year the US produced 737,500 tons of pears. Growing all of those pears is a huge agricultural act. And even if less than 10% of those pears are not sprayed with poison, not subject to chemical fertilizer, it does make a difference. And if the percentage of organic pears produced and purchased each years keeps growing, it makes the world a healthier place. And you are part of that difference.