bulk out
verb1
To become thicker, fatter or more bulky.
2
To cause to be thicker, fatter or more bulky.
3
To become more substantial
4
To cause to be more substantial; to add substance to.
- The pet food was made from meat bulked out with rusk.
Entry derived from the Wiktionary, under licence CC BY-SA 4.0 — list of authors.