It is more about adding muscle mass than it is weight gain. You must eat to fuel your body. After a ME session, your body needs the food to repair and grow. When you go through a heavy squat cycle your body will require you to eat more. It is only natural. My suggestion is to have a solid protien intake, lift as hard and as heavy as you can, eat well, sleep well, and you will grow. I have been well over 300lbs, and am now into the low 280s. I am every bit as strong at 280 as I was at 320. Sometimes just adding too much fat hurts your lifts. Take a look at guys like Donnie Thompson. He was 370lbs+, and while I doubt he could run across the room, he did not carry much fat.
Best meet lifts: 1040squat, 730 bench, 730 deadlift
Best total: 1040-680-730=2450
"This is about strength, not getting a 10.0 form score from the Russian judge" Steve Shaw