A "hefty eater" is someone who consumes large quantities of food, often in an uncontrolled manner. There are several synonyms that can be used to describe such an individual. One possible term is "glutton," which implies excessive indulgence in food or drink. Another option is "gourmand," which highlights a love of good food and a willingness to indulge in rich or delicately prepared dishes. Other synonyms for "hefty eater" might include "voracious," "insatiable," or "overeater," all of which suggest a strong appetite and a propensity for consuming large amounts of food.