(Noun) An individual who conveys a large amount of prejudice to overweight/obese people. Similar to a racist or a sexist, except more tolerable because, other than those with glandular problems, the people targeted by the gluttonist have chosen to be, well, gluttonous.
(at dinner table)
Person A - Can you pass the stuffing?
Person B - SHUT UP FATTY
Person C - Grandma don't be such a gluttonist!