What condition describes a rat that continues to overeat until it gains excessive weight?

The condition described, in which a rat continues to overeat until it gains excessive weight, is best defined by the term that refers to increased appetite or excessive eating behavior, known as hyperphagia. When an organism experiences hyperphagia, it not only exhibits a marked increase in food intake but often leads to weight gain due to the consumption of more calories than necessary for its energy needs.

In the context of study in psychology and physiology, hyperphagia can be observed in various scenarios, including those influenced by psychological factors, hormonal changes, or disruptions in normal regulatory mechanisms for appetite control. Understanding hyperphagia is essential as it can relate to various health conditions and psychological disorders associated with eating behavior.

Other terms listed, such as hypophagia, anorexia, and oligophagia, denote reduced eating or avoidance of food, which does not apply to the condition described in the question.