There are some big things I've learned about myself in the last couple of years. Most of it brought to light through my postpartum inspired weight loss. The biggest of which is that when I'm ready to change... I change. I don't say I'm going to change tomorrow, or Monday, or next week. There is no pre-diet binge justified by all sorts of ridiculous excuses that range from "I've already bought it so I have to finish it up" to "I just need to hit rock bottom".
The thing I've found about myself (and I think it may be universal) is that when I'm pulling that shit I'm not ready. I might (might) pull it together and start some half-assed attempt on that mythical Monday but I won't be able to stick to it. When I'm ready I don't need a "Monday". I don't even need a "tomorrow". It's actually possible to change RIGHT NOW. It's possible to change without really knowing exactly how... without a full plan... without promises. It's possible to change in the middle of the day (believe it). All you have to do is stop doing what's making you crazy.
We all know finishing that box of cookies, or making an exception because "it's on sale", is a lie we're telling ourselves. There is no value in eating up stuff with the sole purpose of postponing eating less and there is no value in saving money on something you wouldn't have bought otherwise.
It isn't starting that is hard... it's stopping.