For instance, this is a problem for chemotherapy patients - the drug therapy causes nausea, which they then associate with food.
Note to self: If I ever have chemotherapy be sure to either only eat foods I already don't like or eat foods that are unhealthy but tasty.
This fits the general pattern of using life change events (like start/end of relationship, illness, study, job) to couple and combine with positive habit changes.
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.