Gosh soda really is horrible huh?

I used to eat fast food about 3-5 times a week and I cut back to only once a week. I have cut back to even less now and don't even remember the last time I have eaten fastfood. Anyway I have been losing weight since doing this. I have cut out soda long before cutting back fast food but the other week I had an itch and purchased a few two liters of shasta punch soda. Low and behold a week after finishing that garbage I gained 3 pounds. Is soda really THAT horrible?