personally, i don't think a person's height or weight play TOO much of a factor... Paul Bragg recommended that even underweight people fast in order to detoxify and heal so that they could gain weight afterwards and be able to achieve a healthier, fuller figure.
it sounds like you have an adequate reserve of tissue. anorexia is more along the lines of having a completely distorted body image... like you've already exhausted all your fat tissues and your body is totally emaciated, yet you still think you look fat.