"Not Fat, Fluffy": Origin and Meaning of the Phrase

The phrase "not fat, fluffy" is a humorous, informal retort—often used by people describing themselves or pets—that plays on the saying "not fat, just fluffy." It is not a standard idiom with a documented literary origin. The variant "not fat and fluffy like my uncle" appears to be a personal or family joke rather than a widely recognized expression.

In essence, the speaker is reframing excess weight as softness or volume from hair/fur, usually in a lighthearted, self-deprecating way. It carries no clinical or formal meaning.