I heard a mother tell this to her scrawny, teenage daughter while I walking down King Street yesterday. The mom told her daughter this in front of the daughter's friend, so clearly the daughter was embarrassed. My heart went out to the mom, because I know that the daughter was being insufferable because she's at that age where everything mom does is the most humiliating thing on earth. The daughter was probably showing off in front of her friend or some such nonsense.
It made me think of all the times I was such an awful, awful teenager to my mom, yet she always supported me unconditionally. And she still does.