An almost surefire way to begin changing the way you eat is to get rid of the microwave oven. This is a sneaky way to start eliminating processed foods from your diet. Eliminate the microwave and you'll no longer buy frozen dinners and other highly processed convenience foods (or microwave popcorn with artificial butter...). Getting these nasties out of your diet should be a priority and without a microwave oven there's little incentive to buy them.
I've seen articles suggesting that microwaving foods actually changes them molecularly (and not for the better). So even if you only use the microwave to cook healthy, unprocessed foods you may be destroying their health-giving properties and in some cases creating dangerous free-radicals and even toxins. It's hard to know what to think about these articles--the research I've seen cited is quite old and obscure. Yet there is a suggestion that evidence has been suppressed by big business so it's hard to know what to think.
Nevertheless, I don't own a microwave and will never have one again. When you cook with healthy whole foods, why risk destroying that goodness, even if the risk is minute?
Here's an article from Dr. Mercola's website citing some of the obscure studies: The Hidden Hazards of Microwave Cooking.