It is easiest to resist temptation on the front end – using your willpower at the first opportunity that a bad impulse knocks. The longer we flirt with the temptation at hand, the harder it is to refuse it.
If you have a weakness for M&Ms, it is far easier to walk past them on the shelf than it is to stroll by the candy jar without digging in, and it is even harder to say no once a few of the chocolate circles are in your hand. You are more likely to have the willpower to pass up those expensive shoes in the store than you are to be able to resist them once you try them on, and you’re even less likely to return them once you’ve brought them home. And while difficult, it is still far easier to make a healthy dish for the potluck than it is to bring your favorite high-calorie treat and hope you don’t eat any of it or to drive right by the “puppies for sale sign” rather than going in “just to pet them.”
For most people, willpower wanes. Capitalize on your strength at the start and implement a hard resistance to your initial urge.