Is using a microwave to cook food safe? Does it change the molecules to inedible substances?

Sorry I don't have a source but microwave radiation dehydrates your food. The energy in this radiation excites the food molecules to heat them as particle speed is directly related to heat. Water boils out of the food - that's why it can sometimes taste a little odd. The food is not supposed to retain any ill effects- the radiation doesn't linger in it to be consumed, but any studies as to the effects will be difficult to perform for a number of reasons: Probably the most glaring of which is our cell phones which are microwave emitters which are almost certainly harmful to us. Thus we are all exposed to microwaves all the time. I wouldn't worry too much about microwaving food but I would use the cell phone sparingly.