Natural VS. Processed Food

Natural foods can be used by the body because they haven't been altered. As such they can also go bad, like stale bread, or any food that is left to sit out too long. The point is that the best foods are the ones that CAN go bad; we want a food to be able to go bad. It's just that we need to eat them before they go bad. This is the whole point of processing - this simple issue is what the whole controversy is about. Longer shelf life equals higher profits. Foods that can't go bad have the longest shelf life. The problem is that the usable nutrients in food are exactly what must be removed in order to have prolonged shelf life. And that's what the science of food processing focuses on: learning better and better ways of taking the perishable nutrients out of foods so that they'll last longer. But what happens when these devitalized Frankenfoods get into our bodies? They're preserved - they're resistant to being changed and broken down. But that's what digestion is: breaking down the foods into usable components. Processed foods are digested poorly, if at all. They clog the digestive tract and make us fat. And cause chronic allergies as the body unsuccessfully tries to expel them.

From: Dr. Tim O'Shea's website check out the link