To be honest, I'm sure that fatty, greasy food isn't the sort of bulk that people need. I'm not denying that it's way too light, but there's little pointing gaining weight if it's horribly non-nutritious. All about balance.
Speaking of weight, over the past month and a half, after having cut out soft drink (soda), fast food (excess fatty foods) caffeine, excess sugar and only eating as much as I need to (not everything that's there) I've gone from 80 kg -> 71 kg. Once I hit 70, I'm going to start getting fit again. I tell you what - you just feel so much better for it.