Matter can neither be created nor destroyed...

Ok, wait, maybe that only applies to energy/electricity, but I think it's matter too right? It takes matter to create new matter, hence ashes to ashes, dust to dust. For instance, when we are kids, say we eat an orange. Our body takes that orange, and turns some of it into energy for moving around, and turns some of it into muscle and fat and bone etc., and then gets rid of whatever parts of the orange it couldn't use. So you might have gotten bigger, butthe orange doesn't exist any more. But... what about people who are over weight. Say someone is 100 lbs over weight. Now they ate enough food to get that way. But then they go on a diet. Now they lose the weight. So they drop 100 lbs. Does that make the planet 100 lbs lighter? Or did that matter go somewhere else? If you burn the calories, then they no longer exist in your fat cells. But people who are losing weight don't go to the bathroom more or anything like that, so the matter goes where? It gets burnt up. So, if everyone became overwieght, or if there were too many people... would that affect the earths orbit. Theoretically speaking of course. And then, if we suddenly had world wide food shortage because of plant disease... people would all lose wieght... would that affect it too? And wait, if we all come from dust... then is there significantly less dust to go around than there was 80 million years ago? Or do we keep refilling our dust supply with star/universe/galactic dust that falls on the earth every night? And if so... is that where all the original dust came from? Because, that means we are all made of space dust... which, when viewed like that, means we are not of this earth, meaning we are all... dun dun dun... Aliens. :-)