Sure, one to two cups of coffee a day is okay; in some cases, it might even keep the doctor away. But what about five or six cups, a few sodas, and a candy bar as a late-afternoon pick-me-up?


BETH HUTSON HAS managed to break up with caffeine more than once. Four years ago, while pregnant, she did it cold turkey. More recently, she replaced nearly all her daily caffeine intake with vitamin-flavored water and other substances.

But her caffeinated love affair has been difficult to shake. The 29-year-old mother, who also runs two small businesses, finds that caffeine helps her stay on track -- coffee, espresso, lattes, energy drinks. Hutson jokes that she hit rock bottom, so to speak, a year ago when she asked her husband to purchase a bulk supply of her favorite energy drink at Costco. So she cut back -- for a while, at least.

“I wish I didn’t feel like I have to have it every day,” she says. “You’re not supposed to be up at two a.m. and not able to sleep because you’ve had caffeine all day.”

In today’s overscheduled, sleep-deprived world, caffeine has never been more omnipresent. From drugstore shelves, it lures us with ice-cold energy logos; from shopping-mall kiosks, it calls, offering a steaming, portable fix. For the hard core, extra shots can be added and there are coffee beans to munch straight up. Meanwhile, new products jockey for shelf space: caffeine-infused candy, chewing gum, and potato chips, among others. According to a 2007 survey conducted by Prince Market Research, roughly half of all Americans drink coffee daily, and 21 percent pop open a caffeinated cola each day.

The good news is that studies have identified relatively few health risks associated with moderate caffeine intake by the average adult. (Children and pregnant women fall into a different category, with little to no caffeine typically recommended.) Coffee -- preferably black, without added calories and fat -- not only sharpens focus and alertness but also appears to have other potential benefits, including reducing the risk of developing type 2 diabetes and Parkinson’s disease.

Still, you can overdose on a good thing. At what point does caffeine cross the line into excess -- or simply become ineffective?

What, really, is moderation? First things first: If you can’t quantify your caffeine habit, start a running tab. Mark down all the sources, such as coffee, soda, and that late-afternoon candy bar. Size does matter. How big was that to-go cup? Individual responses can vary (some people are more caffeine-sensitive), but caffeine’s positive effects -- energy and alertness, among others -- tend to start maxing out at roughly 200 milligrams daily, according to Laura Juliano, PhD, an assistant professor of psychology at American University who helped author one of the most comprehensive reviews to date on caffeine withdrawal. That’s less than the amount in two cups of homebrewed coffee, based on typical averages. One eight-ounce cup of coffee contains about 135 milligrams of caffeine.

How does caffeine work? As many of us know firsthand, caffeine functions as a quick-acting stimulant; peak levels hit our bloodstream within 30 to 45 minutes. Its attention-getting payoff, though, primarily stems from caffeine’s impact on the brain. It appears that by blocking some brain chemicals and boosting the effectiveness of others, including dopamine, caffeine can elevate mood and performance, says John Erwin III, MD, a cardiologist at Scott & White, a teaching hospital in Temple, Texas.

Is all coffee created equal? The short answer is no. Different kinds amount to different levels of caffeine. If you purchase your coffee fix through one of the national chains, check its website for more details. Dr. Erwin also cautions that recent research indicates that coffee made with unfiltered methods, such as French press coffee and espresso, is more likely to raise the levels of low-density lipoprotein (LDL), the so-called bad cholesterol. Brewing coffee with a filter seems to catch many of the cholesterol-raising oils.

Want to boost the benefits? Jump-starting each day with a large soda or a megacup of coffee doesn’t maximize caffeine’s effects, according to intriguing findings from a study published in the journal Sleep. The researchers determined that caffeine works best in low, regular doses -- the equivalent of a quarter cup of coffee each hour. That slow-drip intake may help block adenosine, a brain chemical that accumulates over the day, contributing to sleepiness, says James Wyatt, PhD, the study’s lead author and the director of the Sleep Disorders Service and Research Center at Rush University Medical Center in Chicago. “Most of us are using caffeine wrong,” he says.

Signs that you’ve maxed out: As your consumption increases, you’ll typically need more caffeine to achieve the same effect, Juliano says. Once you take in 250 to 400 milligrams daily, and certainly beyond 400 milligrams, you’re vulnerable to a backlash: jitteriness, anxiety, and uneasiness. Given caffeine’s ability to constrict blood vessels, high doses can promote a faster heartbeat, says Dr. Erwin. The cardiologist cut back a year ago when he felt his own heart racing a bit at times -- and his mood souring. “I felt that I was shorter with people,” he says.

Are you physically dependent? The painful truth is that caffeine, like nicotine, hooks us through a process called negative reinforcement. We continue not because the drug makes us feel particularly good but to avoid the headaches, muddled thinking, and other painful effects of withdrawal. Those symptoms can develop even if we’ve consumed remarkably little -- just 100 milligrams daily, according to Juliano’s comprehensive review.

Trying to cut back? To limit withdrawal symptoms, dial down slowly, Juliano suggests. Your central nervous system -- and, in particular, all of those brain receptors searching for caffeine -- will need weeks or possibly months to adjust, she says. Gradually substitute decaffeinated products or, even better, water. Remember that any headaches or flulike symptoms are temporary, if you only hang in there.

At the same time, get real about your energy-sapping lifestyle. “A lot of people [don’t] develop good habits after college,” says Katherine Tallmadge, MA, RD, an American Dietetic Association national spokesperson. Eating healthy, drinking enough liquids, and getting exercise will boost energy naturally. And don’t push sleep down to the bottom of your to-do list. When life gets busy, “Caffeine is what I immediately default to,” admits Hutson. Her latest goal is to throttle back to only two cups of coffee daily. For his part, Dr. Erwin brags that he’s slashed his consumption in half, restricting himself to a single thermos of home-brewed coffee. The thermos capacity? About five cups.