We’ve all been there before – absolutely committed to being more organized, sticking to our diets our our budgets. But then…the day gets long and your will gets weak. Why is that?

Well, according to a fascinating article on willpower written by John Tierney published in the New York Times Magazine yesterday, our willpower apparently is something that diminishes with every decision we make during the day. Consider this:

Big decisions, small decisions, they all add up. Choosing what to have for breakfast, where to go on vacation, whom to hire, how much to spend — these all deplete willpower, and there’s no telltale symptom of when that willpower is low. It’s not like getting winded or hitting the wall during a marathon. Ego depletion manifests itself not as one feeling but rather as a propensity to experience everything more intensely. When the brain’s regulatory powers weaken, frustrations seem more irritating than usual. Impulses to eat, drink, spend and say stupid things feel more powerful (and alcohol causes self-control to decline further).

He goes on to discuss the role both food (glucose) and habits play in mitigating this issue. It’s incredibly thought-provoking and well worth a read, especially if you are trying to make over a bad habit (or rescue your New Year’s Resolutions).