I'm so FAT, if I didn't eat anything for three weeks would I lose 20lbs?

I don't care that it isn't healthy. I'm not trying to be anorexic or anything, I just need to lose weight and I've tried dieting and exercising with a plan my doctor gave me but it hasn't worked. Everyone says so, not just me. Don't worry, I'm not going to starve myself until I'm a skeleton, I just want to be a size 10 and I'm a size 16 now :( Don't write comments that I'm going to die or anything like that.