If a hot mug of joe or an icy cup of Starbucks is your preferred way to start the day, you've probably noticed that you feel, well, off when don't get your coffee fix. On those especially hectic mornings, you might even sort of hate the world. But that reaction isn't in your head, says Michael J. Kuhar, PhD, professor of neuropharmacology at Emory University.
Caffeine can make you feel energized, alert, and less depressed, Kuhar explains. It can even improve your motor skills and learning ability. When you skip your usual stimulant high, you might feel down, drowsy, sluggish, clumsy, and irritable. You may also experience headaches, and a drop in blood pressure. In a Johns Hopkins University review of studies, researchers found that some people deprived of caffeine even experienced flu-like symptoms, like nausea, vomiting, and muscle pain and stiffness. Yikes.
"You’re basically going through withdrawal," says Kuhar. While you can't become addicted to caffeine in the same sense as people become addicted to drugs, your body can become dependent on it. And since it takes about 24 hours for caffeine to completely leave your system, it makes sense that you wake up craving it.
“Lots of people have their coffee in the morning when they read the newspaper, or when they meet up with friends, and it’s viewed as this very enjoyable moment,” says Kuhar. “And the feelings you get from caffeine reinforce that association. It’s embedded in our lives as this friendly and socially acceptable ritual.”
But there are, of course, reasons you might want to wean yourself off coffee—if you're having trouble sleeping, for example, or dealing with digestive issues. It’s difficult to say when the crappy withdrawal effects will go away, says Kuhar, because it’s different for everyone. And simply seeing a Dunkin Donuts cup—or smelling a freshly brewed pot—can trigger cravings. If you're trying to cut back, it's best to do so gradually, he says, until you’re drinking a more reasonable amount, or none at all.
Nutrition – Health.com