Is there a word to describe a person who gets hungry easily? If there is, are there any antonyms for it?
Merriam Webster defines ravenous as 'being very greedy or eager for food.' Also, gluttonous refers to a person who overeats.
Gourmand is sometimes used as a synonym for 'glutton.'
Bulimia refers to an eating disorder characterized by consuming large amounts of food. This links to an explanation of bulimic.