Most eating disorders are focused on food quantity and resulting weight issues. But orthorexic people can be overweight, extremely thin, or everything in between. Their sole concern is the quality of the food they eat and whether it is in accordance with their rules and restrictions.
My brother, Brad, has an undergraduate degree in mathematics and a master's degree in biology. Right now you're probably picturing him working as a scientist and wearing a white lab coat at work every day. If so, you're wrong. Dead wrong. He's a television writer.