If you are tired of using the phrase "grow fat on something" to describe someone who takes something at the expense of someone else, worry not as there are plenty of synonyms you can use instead. For instance, you can use the phrase "feast on something" to describe an individual who takes advantage of something. Alternatively, you can use "gobble up" to portray a person who consumes something recklessly without considering others. Additionally, you can use "devour" to connote a situation where someone takes something excessively without any consideration or care for those affected. Other synonyms for "grow fat on something" include "consume without consideration", "insatiably indulge", and "gorge without remorse," among others.