So when one starts eating more healthily and cuts out all the junk there are bound to be cravings, often really strong ones. Is there a point at which the cravings for unhealthy foods disappears altogether and eating healthily is no longer a struggle? Or do cravings always persist and we have to do what it takes to live with them?

I have in my mind the idea that junk food is like a drug and that the body goes through a withdrawal period that's really painful but if you can make it through it you can be "purged." Am I way off?

And if this does happen to be true, how long does this withdrawal period last? I know obviously it will vary from person to person. But if you've experienced it, how long did it last for you?