My experiences as a male, 5'11" and 115lb (neither anorexic nor bulimic,) haven't been as bad as most people here. I did get called names in elementary school, and occasionally in middle school, but once I got fed up with the muscular bastards in PE in high school calling me weak I challenged any who thought they were strong to do chin-ups against me. Three of 'em responded; their best was six and I did nineteen.
They left me alone - if you're a thin male and are getting called weak, this is probably a good tactic to try. Why it works: You, if you do any exercise at all, have a decent amount of muscle but very little fat. This makes the ratio of body weight to arm strength a lot lower, and you are able to do more.
I tend to wear very baggy clothing to compensate for it, and I eat a lot (not specifically to gain weight, I just like eating) of high calorie foods.
I still get called 'gay' a lot though, because evidently gay males tend toward anorexia. (Note to those who say "Gay is just an insult, you probably have some habits." Nope, the insults generally go along the lines of "skinny fag")