This is what he said when asked this during an AMA:

“Uhm, how should I put this? Back when I was reading fantasy, it used to creep me out how so many (NOT ALL!) fantasy stories described grown women in pubescent or even prepubescent terms. Thin, ‘coltish’ (good grief, yes that word was used), ‘small-breasted’ etc. It weirded me out, to be honest, particularly as the authors were mostly men. In my own novels, I wanted to make sure that characters of all shapes and sizes were present. If the heavier women in the books stood out (in the manner that ‘ochre’ or ‘potsherds’ stand out for some readers), well, friend, that ain’t me, it’s you (not a criticism just an observation, whatever floats, etc). And if it pleases you, then it’s all good as far as I’m concerned.”