When someone is excessively eager, they might be described as:

The word "voracious" is accurately used to describe someone who is excessively eager, particularly when it comes to their enthusiasm or appetite for something, such as knowledge, food, or experiences. It conveys a sense of intensity and insatiability, indicating that the person has an overwhelming desire to consume or engage with whatever it is they're enthusiastic about. This term captures the fervor and zeal in their eagerness, making it fitting for the description in the question.

Understanding the other choices helps clarify why "voracious" is the best fit. For instance, "sugar-coated" often refers to something that is made to seem more pleasant or acceptable than it actually is, rather than indicating eagerness. "Gloomy" describes a state of sadness or depression, which contrasts sharply with eagerness. "Indifferent" means lacking interest or concern, which again does not align with the idea of being overly eager. The nuance of "voracious" stands out distinctly from these other options, emphasizing an intense and enthusiastic desire.