Off the Chart

I was once told that, according to "the charts" a woman who is 5 feet tall should weigh 100 pounds. For every inch above that, she should weigh an additional 5 pounds. This means that, at 5 ft 1.5 in, I should weigh 107.5 pounds. Yesterday I weighed 197 pounds. (Don't get excited, I haven't made any attempt at diet or exercise, but when I weighed in at 200 pounds a week ago I was pms'ing. I've just lost 3 pounds of monthly bloat---nothing to brag about.) So, anyway, that means that, according to "the charts" I need to lose 90 pounds. That's ALMOST half of what I weigh. I am virtually two people. And I'm NOT pregnant. What I want to know is, where the heck is this supposed chart? Who created it, and what scientific data did they base it on?! HMMMMM??!!! Back in college when I was walking 20 miles a day and eating about 600 calories a day, I got down to 120 pounds. My hair was all falling out and my periods had stopped. But, according to "the chart" I was still 12.5 pounds overweight! The whole thing just adds to my feelings that this is an impossible task, so why bother. I REALLY, REALLY wish I could find a motivating factor big enough to get me to want to bother.......