Eating an organic diet sure sounds healthful — but what does it really mean?

In the food industry, organic fare is free of chemicals and unnatural additives, preservatives or other scientifically created by-products.

For instance, organic produce (fruits and vegetables) is grown without the use of: synthetic pesticides, bioengineered genes (GMOs), petroleum-based fertilizers and sewage sludge-based fertilizers.

"Essentially, the term 'organic' means that all the ingredients are 'real' — not chemically enhanced or in any way produced in a laboratory by a scientist," explains Alina Zhukovskaya, a health coach and organic-nutrition chef.

If you comparison-shop in any produce department, you'll immediately notice that the organic offerings are significantly more expensive. However, that doesn't mean you have to go broke maintaining a diet free of chemicals and preservatives.

Zhukovskaya says, "Not all fruits and vegetables are created equally. Because of the different ways and speeds at which they grow, some you should always try to buy organic. But others you can get away with not buying organic."

Here are the fruits and vegetables Zhukovskaya recommends not buying organic (the so-called "clean 15"):

Asparagus, avocados, bananas, cabbage, cantaloupe, corn, eggplant, grapefruit, kiwi, mangoes, mushrooms, onions, pineapples, sweet peas (frozen), sweet potatoes.

Conversely, here are the "dirty dozen" to always buy organic:

Apples, celery, cherry tomatoes, cucumbers, nectarines, peaches, white/red potatoes, spinach, strawberries, peppers, kale/collard greens, summer squash.