Forget what you’ve heard about how you should start your day.  It’s not about practicing gratitude, meditating, or even going for a run—many successful women are adopting a far more simplistic morning habit: Drinking a large glass of water.  As Business Insider Australia points out, Ariana Huffington and Kat Cole, president of the parent company of Auntie Anne’s, Carvel, and Cinnabon, both start their day with a refreshing glass of hot or cold water (with or without lemon).

Why water instead of coffee?  According to Rania Batayneh, nutritionist and author of The One One One Diet, drinking a glass of water right when you wake up offsets the dehydration your body experiences overnight.  Needless to say, coffee does not.  What’s more, water actually wakes you up in the morning more than you’d think.

“One of the biggest indicators of lethargy or low energy is that you are dehydrated,” Batayneh says. “Because water aids in both body regulation and brain function, it is also closely related to balancing out our moods.”  Ice water essentially “shocks the body” and can “boost your alertness and low energy levels.”

If you’re still not convinced, Batayneh also writes that water kick-starts your metabolism right when you wake up.  As a necessary catalyst for metabolisation, water transports the nutrient-rich carbs and proteins that you consume throughout your body.  To that end, “when we are not adequately hydrated, we can mistake thirst for hunger, which leads us to eat more,” she says.

Is a refreshing glass of water part of your morning routine? If so, share your review of the habit below.