Eating well, exercising and not spending are all fine and well. But my efforts tend to last only a few days before I revert to old destructive habits. How do I channel my stress into more productive outlets than sitting on my bum eating junk and buying things I don't need with money I don't have?

TIA!

Yeah exactly, once the buzz fades away, we fall back doing what we usually do. If you can't generate enough internal determination to stay on the course, you could try jolting your system. What jolts you is probably different to me, I do volunteer work which exposes me to disadvantaged people, which is usually good snapping me back into line. I've also found reading (or watching docs) about the abject poverty experienced by other people - good for warding myself away from excessive spending.

Perhaps try listing out the consequences for not eating well, exercising, etc. The more detail you put into the list, the more you will have to draw upon when you're tempted back to the old habit. However, I find that sometimes when I slip into bad habits that it isn't a conscious choice, it kinda just happens. The only thing that I've found to work in this instance is to identify the times/places where I slip up and associate pain to these images. For example, my mum used to always have candy in a bowl on her bench and when I'd visit I'd automatically start eating it. So I identified this, and I associated this image with pain, I brought the image to mind and then brought images of myself being overweight etc. Then next time I visited my mum, just before my hand hit the bowl, my action was interrupted by these thoughts of disgust, which were stronger then my desire for candy. Anyway, good luck.

Try writing poetry, cooking, photography, exercise, screaming, kickboxing, surfing, meditation, Buddhist chanting, drawing, etc.

just do a good habit