What is defined as a loss of appetite?

The term that is defined as a loss of appetite is "anorexia." This condition is characterized by an intense aversion to food, which can lead to significant weight loss and nutritional deficiencies. Anorexia may be associated with various mental and physical health conditions and is often a symptom of an underlying issue rather than a standalone disorder.

In contrast, bulimia refers to binge eating followed by behaviors to prevent weight gain, such as purging, and does not primarily involve a loss of appetite. Hyperphagia is the term for excessive eating, which is the opposite of loss of appetite. Cachexia describes a complex syndrome involving weight loss, muscle wasting, and a decrease in appetite, typically seen in chronic illnesses, but it is not specifically defined as just a loss of appetite. Therefore, "anorexia" accurately captures the notion of loss of appetite.