Being overweight doesn't mean you are strong, and being heavy really isn't an advantage in a real fight as it effectively makes you a sitting target. If you want proof of this concept then you only need to look at any combat sport, outside of sumo wrestling overweight people tend not to do well at all.
I'd have to second this. Being overweight means you have a medical disorder, not a disability super-power. Of course, if two opponents were at the same skill level, weight would be a very significant factor, hence why their are weight divisions in sports (an elite flyweight would be just that against an equally skilled heavyweight). However, when the skill level is as different as the weight class... well, how common is the image of some five foot black belt karate-kid judo flipping a 6'8, 400lb man? From my experience with martial arts and amateur boxing, it's not strength that determines victory but rather speed, agility, and skill. I myself am quite guilty of racking up a few early round points by hitting my opponent with a light, but very fast jab to the forehead, (1 point blue), and then avoiding or blocking all their kicks and punches to my mid-section.
