I think I might know which one you're talking about.
To Be Worthy by
videokilledtheradio
The Lord of the West has his amber eyes set upon the miko Kagome. After all, he is the only one worthy of such a prize. What is there to hold him back? Obssessive/Possessive Sesshomaru.
I think I remember him thinking to himself that Kagome didn't eat enough to properly sustain his pups should she get (or rather,
when he gets her) pregnant.
EDIT: He noted this in chapter two (I went to
Edit on the toolbar, clicked on
Find, and typed in "pups" as I was viewing the fic). Here's a cut from it:
Watching carefully as she threw her arms over her head in an attempt to rejuvenate her obviously sore muscles, he scowled. The girl looked positively malnourished. How was she to carry his pups in such a state? Sneering as he simply added this to the already impressively long list of his half sibling’s painfully idiotic offenses, he watched the girl stalk off into the underbrush.
Any of this sound familiar?