I saw a great youtube video on how to heal cancer and it prompted me to revisit an age old wisdom about motivation.
Basically, unhealthy living and eating is a slow poison which more often than not doesn't end well. I doubt that anyone lives to die, and in fact to die a slow and painful death. But not everyone is wise enough to foresee cause and effect.
There are two things that motivate us:
1) to gain pleasure, and
2) to avoid pain.
We tend to favour the second point more. Therefore choose to avoid pain over gaining pleasure. The problem is that not everyone can see that with slow processes what seems pleasurable today may contribute to pain on the long run.