I used to be a big Pepsi drinker, until I accepted that I was a big Pepsi drinker. Mostly eliminating sodas from my diet made me lose a fair bit of weight. I still have one a couple times a month, when the wife and I go on a date, but after awhile I just stopped missing the taste, as my body was presumably weaned off the sugar addiction. Eventually I started avoiding things that were sugary, because now if I eat too much sweets it makes me feel ill.
Im still a big guy, but my weight is slowly trending downwards, and I feel better now than I ever did before. It's funny, they tell you that sugar is close to pure energy for the the body, but once I cut back on it I found I had more energy than I did before. I even started running last year.
Anyway, the point of my rambling is to tell you all that they're all pretty much poison, no matter the brand, and you'll start feeling better if you stop drinking them at all. If I could do it, so can you, and you'll thank yourself later. I promise.