Each line in "Secrets" shows a small sign that something is badly wrong with a girl, and each one gets heavier than the last. The untouched plate, the days without eating, the sleepless weeks, the covered arms: they read like a quiet checklist of hidden suffering. The poem never says outright what she's going through, but the imagery suggests an eating problem, exhaustion, and possibly self-harm, all kept out of sight. That fits the title. These are things she hides, and the speaker seems to be the one noticing.
The speaker sounds watchful and helpless, describing rather than rescuing. The pattern of the lines is steady and flat, and the time spans keep stretching, from days to weeks to months to years. That slow stretch makes the last line land hard. "She's been dead for years" probably isn't literal. It suggests she feels emptied out, alive in body but gone inside. The mood is bleak, numb, and hushed, like something painful being said in a whisper.