Perhaps you've been wanting to get into a workout routine and eat healthier. Removing alcohol, even just for a month, can have a cascading effect. Research shows successfully changing one behavior boosts confidence and self-efficacy, which can prompt you to make more healthy changes.
In the case of Dry January, living a hangover-free existance supports other healthy habits: Waking up feeling good makes a gym visit more likely, which can spark a craving for a healthy meal, which can support good sleep, etc.
You may also find you're swapping your usual happy hour time for a dog walk, or drinking a healthy kombucha in place of a not-so-healthy wine.
Happiness expert Gretchen Rubin's habit-change strategy of "identity" could be at play too. You may think: "I'm a non-drinker right now, and non-drinkers make healthy choices."
How effortless other health goals become often surprises people, Nick Allen, co-founder and CEO of Sunnyside, an app and organization that helps people drink more mindfully, told me.
"It's amazing to see, especially for folks where alcohol is a little out of balance in their life, how drinking less, all of sudden, they're unlocking these other health goals that they'd been pursuing for a long time without much success," he said.