Lois has an intense fear of being overweight. although she talks a lot about food, she hardly eats at all. she also has a distorted body image in which she sees herself as "fat" despite the fact that her physician says she is 20% underweight for her height, age, and bone structure. she exercises excessively and still rigidly and obsessively diets despite being 15 pounds lighter than her original dieting goal. she is suffering from ________.