Oh man. There should be a subreddit like /r/ThinPeopleWhoDisplayFatLogicAndAreInTheMedicalField.
If FPS were the place for this, I would totally post stories about my room mate in AIT (Advanced Individual Training- army job training, basically). She was a girl of average weight, not easy on the eyes, but not hard either... she had what I would describe as an "interesting" face.
Anyway, it was the summer before her senior year in nursing school and she wanted to lose like 10 pounds or something over the course of AIT. She told me this on our first day. I thought she was warming up a bit quickly telling me this so early, but not thinking much of it said 'sure buddy. I could use a few myself, so I'll do it with you and we can keep each other motivated.'
Nice girl, but man did she have that fatlogic. Day one, I see her take this pill and I, being a good battle buddy and trying to look out for her, say "Hey, I just want to make sure that you know we're supposed to check in any medication with our sergeants. If they find it during a contraband search and you haven't reported it, you could get in serious trouble." (I won't lie, I was also looking out for myself because if she's taking some unreported meds and a sergeant found it, the sergeant could think it's mine and I'm not getting my ass in trouble). She says "oh it's not medication. It's Hydroxycut!" and starts raving about how great it is and how it's so good for you... hold up. Hydroxycut? Good for you? Didn't I read something about the FDA saying that could cause serious heart problems?! I look on my phone to make sure, all the while she's saying these great things about it and yep. It's super bad for you. I go "Whoa... Uh, you might want to stop taking that." and show her the reports. She says "Oh, that's not true. I know. I'm a nurse." which... no, she was a nursing student, so while I commend her on her progress, not yet a nurse... didn't correct her, let it slide. Figured her body, her choice.
So she kept taking it. This is just one example of her using "I'm a nurse" to say obviously false things about the human body. Other examples include:
Fish is the only meat that's good for you. And only salmon. All other fish are bad.
People who can't pass the PT test might as well be drug addicts.
"Fat free" anything will help you lose weight, no matter how much corn starch is in it.
Crunches will help her lose belly weight (which, someone else said a fatlogic-y relative said that too.)
Spinach is the only vegetable worth eating
Fruit snacks are better than real fruit. (She didn't state this, but they were two separate events that I noticed. The defense of the fat free fruit snacks and later attacking my eating of an orange)
Needless to say, she did not succeed in her goal of losing 10lbs. I, however, lost 20. After 10, I just decided to keep going out of spite, which is a surprisingly awesome motivation. She never took any of my advice because she was "a nurse" while I was "just an engineering student." ... yep.