A: Caffeine itself, in moderate amounts, isn't "bad" for you. (A moderate amount is roughly two eight-ounce cups of coffee per day.) If you want to focus for a short period of time, or stay awake a few extra hours, caffeine can be handy.

But, lots of caffeine, and caffeine from particular sources, has the potential to adversely affect your health. Caffeine, as a stimulant drug, functions similarly to cocaine and heroin, though its effects are (obviously) considerably less harmful. Caffeine affects your brain in three major ways: It constricts blood vessels, releases adrenaline (which makes you more alert), and releases dopamine (which makes you feel good). The constriction of blood vessels can help cure a headache, and the release of adrenaline and dopamine can benefit a studying student (as many of you undoubtedly already know).

Unfortunately, some of us studying students overdo it. Caffeine addiction can result from the consumption of 300 milligrams of caffeine a day-just a little under three cups of coffee, or six cans of Coca-Cola. Suddenly reducing caffeine intake from a sustained level that high will cause fatigue, irritability, tremors, headaches and difficulty sleeping normally. If you're a regular coffee-drinker or soda-imbiber and you want to decrease your intake, it's best to cut back on your caffeinated drinks slowly. Replace one caffeinated drink each day (and then two, three, etc.) with something non-caffeinated until you're back to a "moderate" amount.

But if caffeine is going to be your primary pepper-upper, there are easy guidelines to follow for maximum effect and minimum damage to the rest of your body. First, since caffeine's effects last between four and six hours after intake, stop drinking, well, four to six hours before bed. That should ensure that when your head hits the pillow, you're not stuck wishing you could fall asleep. Second, alternate water with caffeinated drinks-caffeine stimulates urination, so you need to replace all of what you lose with some water. Third, large quantities of caffeine can reduce your body's store of calcium and potassium, resulting in sore muscles and delayed recovery after exercise. (Adding two tablespoons of milk to every cup of coffee should make up the difference.) Further, the carbonation that makes soda (and thus fantastic) can also reduce calcium in your bones, putting you at risk later in life for osteopenia or osteoporosis. (The milk trick, sadly, is not a viably tasty option for soda.) Fourth, one caffeine pill generally contains as much caffeine as two cups of coffee, but without any of the water (duh). Sounds convenient, but it means that you have to be more vigilant about your water consumption lest you become rather dehydrated.

To summarize: Soda-might make you a brittle old person. Coffee-harsh on some people's stomachs, but otherwise okay. Pills-leave you parched. Tea, however, especially of the green variety, can not only deliver moderate amounts of caffeine, but, with plentiful antioxidants, can also protect your heart, your liver, your teeth, etc. from a host of unpleasant ailments (including cancer). (Over 500 studies on green tea have been conducted over the last several years substantiating all sorts of health benefits.)

While you may have thought caffeine was the only way to help you stay awake, you actually have other options to achieve the same end. Three to four ounces of protein (from milk, meat products, nuts, fish, beans or soy) helps you feel more energized and alert because those listed foods contain dopamine. Simple carbohydrates like sugar, on the other hand, create a roller-coaster effect, giving you lots of oomph for a little while … before you crash. Carbs containing fiber-whole grains-can even out the roller coaster by slowing digestion and making your blood sugar more constant over time. Of the available proteins, yogurt is particularly positive because it naturally contains tyrosine, a neurostimulant, and is low in tryptophan, an amino acid (found in those turkeys at Thanksgiving Dinner) that makes you sleepy.

To make a long story short: all stimulants in moderation, yogurt and green tea excepted.

E-mail she@amherst.edu with your questions (we won't ever use your name in the column), and check back in two weeks to see which one we've chosen to tackle. Go forth, and be healthy!