Is it true that prolong exposure to an active microwave or eating microwave prepared foods will give you cancer?
In the first case, probably not. Studies have yet to find a hard link between RF exposure and cancer.
In the second case, definitely not. Microwave radiation isn’t ionizing, and cannot chemically change anything in the food. It can only heat it.
No. Although there is a recent study suggesting it destroys the cancer-preventing agents in food more than any other cooking method does.
“Microwave ovens zap key nutrients” p.14 of this week’s New Scientist.
Microwaves are being used to fight cancer, actually. The waves are focused on tumors and are used to kill the cells. The difference between THOSE microwaves and the one in your oven aren’t the fact that they have similar frequences, but it is, rather, their amplitude (and therefore power) that makes a difference. There just isn’t enough energy from the oven microwaves to do much to your body molecules (or your baked potato) other than cause them to vibrate a lot, which causes them to heat up. Cooking is a secondary result of too much molecular motion. Up the power, though, and you can begin to get bond dissociations, and bad things can happen.
When I say "do things to your body"I mean while you’re standing outside the oven! If you’re inside, then you have as much luck at not being baked as that potato does. Actually, the waves in the oven are focused too, inside that square foot or so of space, and they are insulated in (notice the wiring in the microwave window) so the waves can’t escape. So you aren’t being bombarded with them.
Eating the potato won’t give you any “microwaves” either - as I said, it just started vibrating really fast and got too hot for itself. I suppose it’s possible that the results of cooking a food item can lead to bad chemicals, but that would be food dependent, not microwave dependent.