Hi Nick!!
I went through much the same growing up. At one point my parents heard some actress (yes, and actress) say that microwaving made food unhealthy, so they wanted to get rid of the microwave! I argued the point, and asked why an actress would have a worthwhile opinion on anything besides acting? (I have a special hatred for pontificating celebrities of any ilk). That fad faded, then it was all low-fat, then this, and then that.
If they try and push margarine on you instead of butter, remind them that butter is far healthier than hydrogenated oil (the primary ingredient of margarine). (also, most margarine contains at least some trans-fat, which just about everyone agrees is very bad).
I did, however, find one part of your parents dietary preferences exceedingly disturbing:
Now, that's just plain wrong!