Too little too much :(

So, in my IB Biology class we were talking about healthy eating....Yeah, it was a little awkward when she starting talking about anorexia, but anyway. Mrs. N was like: "It shouldn't be so hard for people to eat healthy. I love Applebee's, they put the number of calories in each dinner on the menu: Some of them are as low as 500 calories!!!" Back up there. My jaw dropped open, I was horrified. They think that 500 is LOW CALORIE? I think that 100 is way to many. I consider anything under 50 as low calorie. Like, really? Is my perception that messed up? If I eat 500 calories I feel horrible, and I consider the day to be a complete fail. I can't loose weight the normal way like everyone else. They talk about eating 1200 calories a day and loosing weight, that doesn't work for me. I gain if I eat that much, the only way I loose is if I eat less then 200. I think I'm at a plateau- my weight just won't change.....500? Are they crazy?