The speaker looks at their own body and sees it with a harsh, almost detached eye. The hips are "fit for a board," a phrase that could mean flat and bony, or something laid out on a table for a meal, and the poem then tells the body to "eat." Flesh is "unwilling," the breasts reduced to "necessity," as if the body were a set of functions the speaker resents having to feed.
The central twist comes in the last lines. The speaker is "ill for want of" something, yet fears "a clear life," one without that ache of lack. Judging by the title, the hunger has become a kind of habit or comfort, and the speaker worries that recovery might leave them exposed to temptation, to "eat not" again. The mood is tense and uneasy, quietly pleading. Short, clipped lines make it feel like a prayer made in the middle of a struggle, with no resolution offered.