Bottom-heavy is a tiny poem that turns a body-image joke into something warmer. The speaker compares themselves to a pear, a fruit that is narrow on top and wide below, and seems to accept that shape with good humor. The title already tells us where the weight sits, and the poem doesn't apologize for it.
The first lines suggest a kind of settling. "A neglected convenience / to settle in at last" could describe the lower body as something overlooked that finally gets its due, a place where one can rest. There is a sense of relief, even of coming home to oneself. Then the closing lines play with the idea of size: "the biggest sum" hints at totals and adding up, as if the speaker's fullest part is also the part that counts most.
The mood is light, wry and content. Judging by the wording, the speaker feels self-aware but at ease, turning what some might call a flaw into a quiet pleasure.