The mating bond is accepted when a female offers the male food but it all seems to start with the males encouraging their mates to eat out of concern for their health:

FEYSAND

“Eat breakfast with me,” he said.

There was a note in those words that made me pause. A note of what I could have sworn was desperation. Worry.

I twisted, my loose clothes sliding over my shoulders, my waist. I hadn’t realized how much weight I’d lost. Despite things creeping back to normal.

NESSIAN

Nesta angled her head, golden-brown hair sliding over her too-thin shoulder.

“Do I look like I need four hours to become presentable?”

Cassian said at last, “You look like you could use a few big meals,

ELUCIEN

Too thin.

She must not be eating at all.

How can she even stand?

Her too-thin shoulders seemed to curve inward.

the ravages of her fasting were evident enough.

“There’s a plate of biscuits. Would you like one?”