1. Ignoring goals, tabooing / identifying with methods - the opposite of Beeminder, even the opposite of SMART
Suppose I want to lose weight. Have a general idea of how much and how fast, and decide on the method. Then I ignore the goal and focus on the method. I ignore both the long-term and short-term goal (no Beeminder), ignore the measurement (SMART), ignore all the common wisdom here. The reason I ignore them that I want to avoid constantly haggling with myself, using the soda example, "Surely this one glass will not set me back much?" and instead I identify with the method, such as, simply shaping my identity as a person who does not drink soda, period. Instead of being conscious of the goal, just focus on this new identity. Without a goal in mind, there is nothing to haggle about and that makes it work. So there is not that kind of "Perhaps, this is a special case because X so half a glass should be allowed..." instead, it is just taboo, because it violates my new sense of self of a person who just does not do that. The beauty of this solution that there is nothing to haggle about. It is a harnessing of the cognitive dissonance and protect-your-identity mechanisms, if the new self is the sort of person who just does not drink soda then the only way to not get dissonant and to preserve the identity is to not do so. This, so far, seems to be surprisingly easy for me. It is similar to religious taboos, like people who don't eat X because then they could no longer consider themselves a pious follower of religion Y and it would shake their identity. You could say it is a custom-made nanoreligion each time. Being pious by not violating self-made taboos, preserving the identity of the pious person, without having keep the goal in consciousness.
2. Don't fight The Boss
Someone casually dropped on stopdrinking.reddit.com "It is not about fighting your urges, it is about stopping to fight your better judgement." Precisely. There is a Higher Self (say, Superego) telling me to live healthy and a Lower Self (Ego, Id) telling me to indulge in urges and cravings. Identify with Higher Self, and it is a constant fight with the Lower Self. Identify with the Lower Self and all I need to do is to surrender to the commands of the Higher Self. It does not feel good, but in this case it is okay to not feel good. I call the Higher Self The Bos. It is like "I really want to do X but The Boss does not let me do so. It makes me feel depressed. It is okay. Just accept the feeling and don't fight The Boss. You can never beat The Boss. Just surrender and accept your fate." It is also a nano, well, in this case a microreligion because it is more consistent than the one-off taboos of nanoreligions. Identifying with Lower Self is a bit of an "I am a sinner" thing, and this surrender to The Boss feels a bit religious, a bit close to the AA and 12-step methods.
One other approach to avoid constantly haggling with yourself (which I agree is draining and annoying) but without giving up the temptation completely is just to randomize whether you act on your urges.
At an old job, I used to want to go out to get a cookie in the afternoon a couple times a week. I didn't want to act on the urge every time I felt it, but I also didn't want to solve the problem by making afternoon cookies verboten forever. So, when I wanted a cookie, I went to random.org and set it to pick a number from 1-3. If it was a 1, I got a cookie, if not, not.
No decision fatigue, no being "bad cop" to myself, and I got to enjoy a thing I wanted intermittently!
A general form of deciding on a process and committing to it. Take the decision out of your hands. Ask the Magic 8 Ball.
A trick I've read (Baumeister?) is to just postpone the eating. Have a plan to have a cookie tomorrow. Or at the end of the week. Knowing that you're going to have one is supposed (has been shown?) to lessen the immediate temptation.
In the random and postponement cases, your mind gets the satisfaction of maybe getting a cookie now or surely getting a cookie later. That anticipation is supposed to have it's own satisfaction that makes the actual eating less motivating.