neosyllogy saidYou guys are just being jerks, it's really not necessary. He's not spamming, so what if he asks a question you think has an obvious answer.
In any case, the question isn't that unreasonable. Personality probably affects food choices, particularly when those choices are centered around issues of personal health, animal cruelty, and environmental concern. Really, dismissing the question is kind of stupid. Get a hobby and stop picking on people.
Actually, a folk belief that food affects behavior has been around for a long time. It even appears in Oliver Twist
by Dickens. The excerpt below is when Oliver has rebelled against his cruel treatment as an undertaker's apprentice, whereupon the family has locked him in a cellar and called for the local beadle, Mr. Bumble, to whom Oliver remains defiant:'Oh, you know, Mr. Bumble, he must be mad,' said Mrs. Sowerberry. 'No boy in half his senses could venture to speak so to you.'
'It's not Madness, ma'am,' replied Mr. Bumble, after a few moments of deep meditation. 'It's Meat.'
'What?' exclaimed Mrs. Sowerberry.
'Meat, ma'am, meat,' replied Bumble, with stern emphasis. 'You've over-fed him, ma'am. You've raised a artificial soul and spirit in him, ma'am, unbecoming a person of his condition: as the board, Mrs. Sowerberry, who are practical philosophers, will tell you. What have paupers to do with soul or spirit? It's quite enough that we let 'em have live bodies. If you had kept the boy on gruel, ma'am, this would never have happened.'
'Dear, dear!' ejaculated Mrs. Sowerberry, piously raising her eyes to the kitchen ceiling: 'this comes of being liberal!'
The liberality of Mrs. Sowerberry to Oliver, had consisted of a profuse bestowal upon him of all the dirty odds and ends which nobody else would eat; so there was a great deal of meekness and self-devotion in her voluntarily remaining under Mr. Bumble's heavy accusation. Of which, to do her justice, she was wholly innocent, in thought, word, or deed.
The OP may also be questioning a psychological component to dietary choices, as well. Though not about food, I do recall various studies over the years that suggested moderate drinkers are the best emotionally adjusted, compared to total abstainers as well as to alcoholics, who are both the least adjusted. It has nothing to do with the alcohol content itself, but rather the process of choosing whether to drink or not, and how much.
Since food is usually a choice (unless you're Oliver Twist), can its choice reflect personality? But I'd be careful about assuming what traits a vegetarian might generally have, however: one of the world's most best-known vegetarians was Adolph Hitler.