Because you are a disgusting fat-body.
5 seconds sound clip from the Jaws (1975) movie soundboard.
You can hear this line at 00:25:02 in the Blu-ray version of the movie.
Quote context
[...]
- Are you allowed to eat jelly doughnuts?
- Sir, because I'm too heavy, sir.
- Because you are a disgusting fat-body.
- Then why did you hide a jelly doughnut in your footlocker?
- Sir, because I was hungry, sir.
- Private Pyle has dishonored himself and dishonored the platoon.
[...]