Final answer:
The statement from an adolescent client with anorexia nervosa that is a sign of cognitive distortion is 'If I eat one piece of candy, I may as well eat ten,' representing the 'all-or-nothing' thinking pattern typical in this disorder.
Step-by-step explanation:
A nurse assessing an adolescent client with anorexia nervosa will be looking for various signs of cognitive distortion which is a hallmark of this eating disorder. Out of the statements provided, the one that is a clear sign of cognitive distortion is: "If I eat one piece of candy, I may as well eat ten." This statement exhibits the "all-or-nothing" thinking that is common in individuals with anorexia nervosa, where the client sees no middle ground or believe in partial success, which can lead to unhealthy restrictive behaviors or anxiety over food intake.
Anorexia nervosa is an eating disorder in which people consistently eat very little and have an obsessive fear of gaining weight. Individuals with this disorder typically have distorted body image and see themselves as overweight even when they are underweight. In severe cases, without treatment, it can lead to critical health issues and even death.