If you really love your Valentine, don't give her an enormous box of fancy candies. The most thoughtful gift may be a small - make that 1 ounce - piece of dark chocolate, says Lawrence Cheskin, associate professor of medicine and human nutrition at the Johns Hopkins Bloomberg School of Public Health and director of the gastroenterology division at Johns Hopkins Bayview Medical Center.

Chocolate, used by the Aztecs as an aphrodisiac, has been called "the food of gods" for centuries. In recent years, it has been shown to offer some health benefits. But, like so much in life, the sugary treat is best in moderation.

There has been a lot of buzz in the media about chocolate as a healthful food. Do chocolate lovers dare hope this is the case?

The studies are suggesting that there may be some health benefits to eating chocolate, although there are some caveats that go along with that.

What it is about chocolate that may be healthful?

It is probably due to the flavanols, which are a kind of plant sterol that is also found in the new margarines that lower cholesterol, and in red wine and tea. What they seem to do is slightly decrease blood pressure and improve lipid levels in the blood.

Like aspirin, they also seem to inhibit clotting so thereby may decrease risks of hypertension and heart disease.

Does this mean that we can eat chocolate doughnuts for breakfast and chocolate bars for lunch?

That is where the downside comes in. You have to be aware that you can probably get the same health benefit by eating lots of fruits and vegetables.

And the danger with chocolate is that you also are probably eating lots of calories and fat. There are some kinds of chocolates that, though they have high fat, also have high amounts of flavanols; so you can eat less of them and get the health benefits.

What kind of chocolate should we be eating?

Dark chocolate - but not everyone likes it because it has a more bitter taste than milk chocolate. But it has higher levels of flavanols.

Look for chocolate that has about 70 percent by weight of cacao from the cocoa bean. But be careful: Manufacturers sometimes try to remove the bitter taste of dark chocolate with a process called alkalizing or a Dutch process - and that process removes the flavanols.

Why is chocolate considered such a romantic gift?

Chocolate does have some other potential benefits if you are talking about, shall we say, romance. It contains theobromine, which, like caffeine, stimulates the body's endorphins. It also has anandamide, another euphoria stimulant that produces positive mood effects. And it contains phenylethylamine, which is sometimes called the "love chemical" because it is a precursor of dopamine. Dopamine is a brain neurochemical that can trigger lust, combats depression and releases testosterone.

The down side is that if you eat too much chocolate, you will have consumed too many calories and fat, and that is a negative for sexuality.

What do you tell your patients about chocolate?

If you like chocolate and you find it romantic or stimulating, by all means eat some. But the problem with chocolate is that we tend to add butterfat and sugar to make it. Eating just the cocoa bean would be the healthiest thing to do. So limit the amount you eat and eat dark chocolate - it has better health benefits than white or milk chocolate. And if you are going to have even an 8- or 9-ounce bar, then you are asking for trouble. You are talking about 1,000 calories, and that is half the calories women need daily.