XKCD nails it, as always. But there’s more.
My addiction was to Diet Coke, of which I was drinking two cans a day during the week. While the medical evidence on aspartame is pretty unanimous, I felt like I always wanted to eat more back then. And the constant caffeine infusions weren’t great for my heart health, either.
I quit Diet Coke cold turkey over three years ago, along with all other sodas. I rarely miss it.