If your New Year’s resolution is to rein in your sweet tooth, you might want to drop the Christmas cookie currently on its way to your mouth. We know it seems a little early to be turning over a new leaf—of lettuce, in your case—but getting in a practice round before 2020 could give you the best possible chance of success.

As The New York Times explains, we often set New Year’s resolutions that are either too general or too difficult. It’s not easy to stick to an unclear goal like “making healthy choices” or “being more financially responsible,” because it’s not totally obvious what that entails. Having said that, defining a resolution in no uncertain terms doesn’t necessarily ensure that you’ll follow it—since it’s possible that those terms are just way too hard to adhere to. If your clear-cut goal is to cut out all processed foods, for example, but you’ve spent the last decade relying on bagged snacks and frozen individual dinners as your main source of energy, you might find yourself starving, confused, and standing in the chip aisle at your grocery store on January 4.

In a nutshell, there are a lot of factors to consider when devising a New Year’s resolution, and it helps to have a little extra time to work out any unforeseen kinks before you debut the new you come January 1. Maybe you, unbeknownst to anyone, try cutting out all processed foods on December 27 this year, fail spectacularly, and revise your resolution to “replacing one processed meal per day with a homemade one.”

Beginning early will also give you a head start when it comes to seeing results in 2020, which is another incentive to stay committed to your resolution. According to a University of Chicago study [PDF] from 2016, people are more motivated to stick to their long-term goals when they’re instantly rewarded for them. If you’re not immediately seeing the number on the scale go down or the number in your bank account go up, for instance, you might lose faith and give up completely. But, with a week or two of resolution-ing already behind you when the new year kicks off, it might make you feel like your results are a little more instantaneous.

Can’t quite bring yourself to abandon that cookie just yet? That’s OK, too—here are 10 other ways to help you stick to your New Year’s resolution.

[h/t The New York Times]