Of course not. I are one. Sort of.
Clothing size has nothing to do with objective reality. It's the fashion industry that declares who is plus and who is not. It has nothing to do with us, our body types, or whether we're healthy. It's a matter of selling clothes! And we fall for it, worrying ourselves that we're not acceptable.
I've watched those little numbers zoom all over the place. Admittedly, I went to elementary school with the dinosaurs, but I recall that size 12 was the size of choice for grown women in those days! Size 10 meant you were on the almost-too-skinny side. Marilyn Monroe had a top measurement that might have bumped her up to a 14 (I've heard 16 also), but the cameras still liked her, right? It was just that those *numbers* were used differently then.
Not really very long ago "plus" began at size 18. Then it became 16, and 14, and now 12. Size 10 should be relegated to the plus bin any time now.
Likewise, sizes on the other end have been marked with lower and lower numbers. There hasn't always been a size zero. What will come next? Size minus four? Here's a thought: will women really *buy* size minus four? Or will they laugh?
Even one size isn't treated the same by the manufacturers. I can wear a 10 in some brands, and have to look for 14s in others. A friend told me once that the size labels in the really high-end stores (the ones I can't afford to breathe the air in) are totally different, so that what would be, say, a size 8 most everywhere else might be a size 4 in that shop.
We real people need to buy clothing that fits us and makes us look good, and laugh those size tags to scorn. We shouldn't give them permission to tell us who we are.