For me, getting soda on cans made a huge difference - the parent didn’t estimate the sugar content if a 2l bottle. Anyhow having cans both let’s me off the hook for having one, keeps me from rationalizing that I don’t want to waste it by letting it get flat, and I find it easier to limit myself to only one per day

(Plus it’s diet. I’m not sure that’s entirely better so still worth limiting, but it’s not sugar, or empty calories)