For Valentine's Day, how about an éclair?

Just one sentence from "Missing Micrograms Set a Standard on Edge" by Sarah Lyall in yesterday's New York Times:

"Because a kilogram is defined as whatever the mass of the prototype is, it does not, for definitional purposes, matter if the prototype loses mass, or indeed packs on the micrograms by spending all its free time gorging on éclairs: it is still a kilogram."