The speaker sits down to a meal and finds that nothing fits anymore. They cry out to the plate and to a spoon that feels like the wrong one, as if even the simplest tools of eating have turned strange. "I cannot eat as we used to" suggests something has changed, perhaps a shared habit or a relationship, though the poem never says what.
The "evils" the speaker orders for dinner, along with the ice and the gin, hint at appetites that have turned into something harmful, maybe drink or a habit of self-punishment. That is an inference, since the poem stays vague. The last lines are the most telling: the speaker is "less and less able to bear it," even though what they served up was "light." So the trouble may be less about the food than about the weight of whatever it stands for.
The mood is tired, uneasy and a little wry. The short, broken lines make the speaker sound worn down, and the title, "Too rich," fits that feeling of being overfull.