when you eat your body goes into storage mode.. you keep insulin levels high
so eating more food, more often will cause weight gain.. that is just common sense and why america is so fucking fat.
however don't make the mistake of gaining too much, too fast. if you do your gains will be crap. in your gym most of the guys are just fat perma bulkers. it isn't hard to stick your ass with steroids, drink lots of shakes, and eat meat all day and gain weight. but is it good weight? no, they look like shit.. just fat and strong perma bulkers.