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Men who were fat when younger, and are now cripplingly insecure about themselves/their relationships may be said to have Fat Boy Syndrome (FBS). A man with FBS may or may not talk constantly about his weight/workout routine and/or his eating habits. He usually also talks about his insecurities ad infinitum. Men with FBS have a tendency to be overemotional, latch on to those who show any sort of interest in them, and be generally annoying.
Man with FBS: So, she says she likes me, but I don't know if she really does! I love her so much, and I'm just so scared that she'll realize she isn't into me....I should really hit the gym later, I'm feeling a little chubby...do these pants make me look fat?

Me: GO TALK TO A THERAPIST ABOUT YOUR FAT BOY SYNDROME!!1!!11!1
by j. rose October 13, 2011

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When all of your pictures on online dating sites do not indicate your actual girth and you say "Oh, my only disappointment is I am a husky guy" or something to that effect. This progresses into you taking out your insecurities on possible dating options and attempting to be far more sexual through mediums like the internet or texting, then you actually are in real life to overcompensate. This also leads to you not even allowing the process to progress anywhere because you are so use to people not giving you a chance because of your past rejection, presumably due to how you look. Defensiveness and oversensitivity ensues.

(see also: fat girl syndrome)
A guy I met at the bar from a dating site that totally had fat boy syndrome.
by clavicle8 May 02, 2011

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