"If you give in once, you'll give in twice" -Sir Alex Ferguson

Giving in once, will lead to giving in again, sooner than later.

First, you tell your brain that it's ok to give in.

Second, you realize that giving in once isn't THAT big of deal, and nothing happened.

But, The more you give in, the more you give in.

The trick is, make a plan to have those moments where built in. Plan for the cheat meal, the drinks on the weekend, whatever it is that you want to do, just plan for it.